diff --git a/simpeg_drivers-assets/uijson/direct_current_2d_forward.ui.json b/simpeg_drivers-assets/uijson/direct_current_2d_forward.ui.json
index 723664da..62882450 100644
--- a/simpeg_drivers-assets/uijson/direct_current_2d_forward.ui.json
+++ b/simpeg_drivers-assets/uijson/direct_current_2d_forward.ui.json
@@ -105,7 +105,7 @@
     "model_type": {
         "choiceList": [
             "Conductivity (S/m)",
-            "Resistivity (ohm-m)"
+            "Resistivity (Ohm-m)"
         ],
         "main": true,
         "group": "Mesh and models",
diff --git a/simpeg_drivers-assets/uijson/direct_current_2d_inversion.ui.json b/simpeg_drivers-assets/uijson/direct_current_2d_inversion.ui.json
index 467bdb80..95b75605 100644
--- a/simpeg_drivers-assets/uijson/direct_current_2d_inversion.ui.json
+++ b/simpeg_drivers-assets/uijson/direct_current_2d_inversion.ui.json
@@ -125,7 +125,7 @@
     "model_type": {
         "choiceList": [
             "Conductivity (S/m)",
-            "Resistivity (ohm-m)"
+            "Resistivity (Ohm-m)"
         ],
         "main": true,
         "group": "Mesh and models",
diff --git a/simpeg_drivers-assets/uijson/direct_current_3d_forward.ui.json b/simpeg_drivers-assets/uijson/direct_current_3d_forward.ui.json
index da8ba5a9..1a93c370 100644
--- a/simpeg_drivers-assets/uijson/direct_current_3d_forward.ui.json
+++ b/simpeg_drivers-assets/uijson/direct_current_3d_forward.ui.json
@@ -31,7 +31,7 @@
     "model_type": {
         "choiceList": [
             "Conductivity (S/m)",
-            "Resistivity (ohm-m)"
+            "Resistivity (Ohm-m)"
         ],
         "main": true,
         "group": "Mesh and models",
diff --git a/simpeg_drivers-assets/uijson/direct_current_3d_inversion.ui.json b/simpeg_drivers-assets/uijson/direct_current_3d_inversion.ui.json
index 48b90fee..5eba2847 100644
--- a/simpeg_drivers-assets/uijson/direct_current_3d_inversion.ui.json
+++ b/simpeg_drivers-assets/uijson/direct_current_3d_inversion.ui.json
@@ -56,7 +56,7 @@
     "model_type": {
         "choiceList": [
             "Conductivity (S/m)",
-            "Resistivity (ohm-m)"
+            "Resistivity (Ohm-m)"
         ],
         "main": true,
         "group": "Mesh and models",
diff --git a/simpeg_drivers-assets/uijson/direct_current_batch2d_forward.ui.json b/simpeg_drivers-assets/uijson/direct_current_batch2d_forward.ui.json
index 34a966a5..8628a630 100644
--- a/simpeg_drivers-assets/uijson/direct_current_batch2d_forward.ui.json
+++ b/simpeg_drivers-assets/uijson/direct_current_batch2d_forward.ui.json
@@ -88,7 +88,7 @@
     "model_type": {
         "choiceList": [
             "Conductivity (S/m)",
-            "Resistivity (ohm-m)"
+            "Resistivity (Ohm-m)"
         ],
         "main": true,
         "group": "Mesh and models",
diff --git a/simpeg_drivers-assets/uijson/direct_current_batch2d_inversion.ui.json b/simpeg_drivers-assets/uijson/direct_current_batch2d_inversion.ui.json
index 04de4956..7c19bce0 100644
--- a/simpeg_drivers-assets/uijson/direct_current_batch2d_inversion.ui.json
+++ b/simpeg_drivers-assets/uijson/direct_current_batch2d_inversion.ui.json
@@ -107,7 +107,7 @@
     "model_type": {
         "choiceList": [
             "Conductivity (S/m)",
-            "Resistivity (ohm-m)"
+            "Resistivity (Ohm-m)"
         ],
         "main": true,
         "group": "Mesh and models",
diff --git a/simpeg_drivers-assets/uijson/fdem1d_forward.ui.json b/simpeg_drivers-assets/uijson/fdem1d_forward.ui.json
index 33192e3c..af248f1b 100644
--- a/simpeg_drivers-assets/uijson/fdem1d_forward.ui.json
+++ b/simpeg_drivers-assets/uijson/fdem1d_forward.ui.json
@@ -84,7 +84,7 @@
     "model_type": {
         "choiceList": [
             "Conductivity (S/m)",
-            "Resistivity (ohm-m)"
+            "Resistivity (Ohm-m)"
         ],
         "main": true,
         "group": "Mesh and models",
diff --git a/simpeg_drivers-assets/uijson/fdem1d_inversion.ui.json b/simpeg_drivers-assets/uijson/fdem1d_inversion.ui.json
index 6199b8db..dd5510db 100644
--- a/simpeg_drivers-assets/uijson/fdem1d_inversion.ui.json
+++ b/simpeg_drivers-assets/uijson/fdem1d_inversion.ui.json
@@ -132,7 +132,7 @@
     "model_type": {
         "choiceList": [
             "Conductivity (S/m)",
-            "Resistivity (ohm-m)"
+            "Resistivity (Ohm-m)"
         ],
         "main": true,
         "group": "Mesh and models",
diff --git a/simpeg_drivers-assets/uijson/fdem_forward.ui.json b/simpeg_drivers-assets/uijson/fdem_forward.ui.json
index 24f6eedb..c72f54d4 100644
--- a/simpeg_drivers-assets/uijson/fdem_forward.ui.json
+++ b/simpeg_drivers-assets/uijson/fdem_forward.ui.json
@@ -44,7 +44,7 @@
     "model_type": {
         "choiceList": [
             "Conductivity (S/m)",
-            "Resistivity (ohm-m)"
+            "Resistivity (Ohm-m)"
         ],
         "main": true,
         "group": "Mesh and models",
diff --git a/simpeg_drivers-assets/uijson/fdem_inversion.ui.json b/simpeg_drivers-assets/uijson/fdem_inversion.ui.json
index 76991d4c..acd5692f 100644
--- a/simpeg_drivers-assets/uijson/fdem_inversion.ui.json
+++ b/simpeg_drivers-assets/uijson/fdem_inversion.ui.json
@@ -92,7 +92,7 @@
     "model_type": {
         "choiceList": [
             "Conductivity (S/m)",
-            "Resistivity (ohm-m)"
+            "Resistivity (Ohm-m)"
         ],
         "main": true,
         "group": "Mesh and models",
diff --git a/simpeg_drivers-assets/uijson/induced_polarization_2d_forward.ui.json b/simpeg_drivers-assets/uijson/induced_polarization_2d_forward.ui.json
index d08f22cf..e90f20d4 100644
--- a/simpeg_drivers-assets/uijson/induced_polarization_2d_forward.ui.json
+++ b/simpeg_drivers-assets/uijson/induced_polarization_2d_forward.ui.json
@@ -105,7 +105,7 @@
     "model_type": {
         "choiceList": [
             "Conductivity (S/m)",
-            "Resistivity (ohm-m)"
+            "Resistivity (Ohm-m)"
         ],
         "main": true,
         "group": "Mesh and models",
@@ -121,7 +121,7 @@
         "isValue": true,
         "parent": "mesh",
         "label": "Background",
-        "tooltip": "Background model in the 'Model units' (S/m or ohm-m).",
+        "tooltip": "Background model in the 'Model units' (S/m or Ohm-m).",
         "property": "",
         "value": 0.001
     },
diff --git a/simpeg_drivers-assets/uijson/induced_polarization_2d_inversion.ui.json b/simpeg_drivers-assets/uijson/induced_polarization_2d_inversion.ui.json
index 999d02a8..5664233a 100644
--- a/simpeg_drivers-assets/uijson/induced_polarization_2d_inversion.ui.json
+++ b/simpeg_drivers-assets/uijson/induced_polarization_2d_inversion.ui.json
@@ -124,7 +124,7 @@
     "model_type": {
         "choiceList": [
             "Conductivity (S/m)",
-            "Resistivity (ohm-m)"
+            "Resistivity (Ohm-m)"
         ],
         "main": true,
         "group": "Mesh and models",
@@ -140,7 +140,7 @@
         "isValue": true,
         "parent": "mesh",
         "label": "Background",
-        "tooltip": "Background model in the 'Model units' (S/m or ohm-m).",
+        "tooltip": "Background model in the 'Model units' (S/m or Ohm-m).",
         "property": "",
         "value": 0.001
     },
diff --git a/simpeg_drivers-assets/uijson/induced_polarization_3d_forward.ui.json b/simpeg_drivers-assets/uijson/induced_polarization_3d_forward.ui.json
index e9f559d4..889ca714 100644
--- a/simpeg_drivers-assets/uijson/induced_polarization_3d_forward.ui.json
+++ b/simpeg_drivers-assets/uijson/induced_polarization_3d_forward.ui.json
@@ -31,7 +31,7 @@
     "model_type": {
         "choiceList": [
             "Conductivity (S/m)",
-            "Resistivity (ohm-m)"
+            "Resistivity (Ohm-m)"
         ],
         "main": true,
         "group": "Mesh and models",
diff --git a/simpeg_drivers-assets/uijson/induced_polarization_3d_inversion.ui.json b/simpeg_drivers-assets/uijson/induced_polarization_3d_inversion.ui.json
index 96913778..79d43580 100644
--- a/simpeg_drivers-assets/uijson/induced_polarization_3d_inversion.ui.json
+++ b/simpeg_drivers-assets/uijson/induced_polarization_3d_inversion.ui.json
@@ -56,7 +56,7 @@
     "model_type": {
         "choiceList": [
             "Conductivity (S/m)",
-            "Resistivity (ohm-m)"
+            "Resistivity (Ohm-m)"
         ],
         "main": true,
         "group": "Mesh and models",
diff --git a/simpeg_drivers-assets/uijson/induced_polarization_batch2d_forward.ui.json b/simpeg_drivers-assets/uijson/induced_polarization_batch2d_forward.ui.json
index 0917f832..79ffccd7 100644
--- a/simpeg_drivers-assets/uijson/induced_polarization_batch2d_forward.ui.json
+++ b/simpeg_drivers-assets/uijson/induced_polarization_batch2d_forward.ui.json
@@ -88,7 +88,7 @@
     "model_type": {
         "choiceList": [
             "Conductivity (S/m)",
-            "Resistivity (ohm-m)"
+            "Resistivity (Ohm-m)"
         ],
         "main": true,
         "group": "Mesh and models",
diff --git a/simpeg_drivers-assets/uijson/induced_polarization_batch2d_inversion.ui.json b/simpeg_drivers-assets/uijson/induced_polarization_batch2d_inversion.ui.json
index e8fdbf7c..b9007098 100644
--- a/simpeg_drivers-assets/uijson/induced_polarization_batch2d_inversion.ui.json
+++ b/simpeg_drivers-assets/uijson/induced_polarization_batch2d_inversion.ui.json
@@ -107,7 +107,7 @@
     "model_type": {
         "choiceList": [
             "Conductivity (S/m)",
-            "Resistivity (ohm-m)"
+            "Resistivity (Ohm-m)"
         ],
         "main": true,
         "group": "Mesh and models",
diff --git a/simpeg_drivers-assets/uijson/joint_surveys_inversion.ui.json b/simpeg_drivers-assets/uijson/joint_surveys_inversion.ui.json
index 28815d75..62557f66 100644
--- a/simpeg_drivers-assets/uijson/joint_surveys_inversion.ui.json
+++ b/simpeg_drivers-assets/uijson/joint_surveys_inversion.ui.json
@@ -71,7 +71,7 @@
     "model_type": {
         "choiceList": [
             "Conductivity (S/m)",
-            "Resistivity (ohm-m)"
+            "Resistivity (Ohm-m)"
         ],
         "main": true,
         "group": "Mesh and models",
diff --git a/simpeg_drivers-assets/uijson/magnetotellurics_forward.ui.json b/simpeg_drivers-assets/uijson/magnetotellurics_forward.ui.json
index e6942efe..8cdecac5 100644
--- a/simpeg_drivers-assets/uijson/magnetotellurics_forward.ui.json
+++ b/simpeg_drivers-assets/uijson/magnetotellurics_forward.ui.json
@@ -78,7 +78,7 @@
     "model_type": {
         "choiceList": [
             "Conductivity (S/m)",
-            "Resistivity (ohm-m)"
+            "Resistivity (Ohm-m)"
         ],
         "main": true,
         "group": "Mesh and models",
diff --git a/simpeg_drivers-assets/uijson/magnetotellurics_inversion.ui.json b/simpeg_drivers-assets/uijson/magnetotellurics_inversion.ui.json
index 27708817..3a34206e 100644
--- a/simpeg_drivers-assets/uijson/magnetotellurics_inversion.ui.json
+++ b/simpeg_drivers-assets/uijson/magnetotellurics_inversion.ui.json
@@ -270,7 +270,7 @@
     "model_type": {
         "choiceList": [
             "Conductivity (S/m)",
-            "Resistivity (ohm-m)"
+            "Resistivity (Ohm-m)"
         ],
         "main": true,
         "group": "Mesh and models",
diff --git a/simpeg_drivers-assets/uijson/tdem1d_forward.ui.json b/simpeg_drivers-assets/uijson/tdem1d_forward.ui.json
index 02ceba28..b4d6c39f 100644
--- a/simpeg_drivers-assets/uijson/tdem1d_forward.ui.json
+++ b/simpeg_drivers-assets/uijson/tdem1d_forward.ui.json
@@ -98,7 +98,7 @@
     "model_type": {
         "choiceList": [
             "Conductivity (S/m)",
-            "Resistivity (ohm-m)"
+            "Resistivity (Ohm-m)"
         ],
         "main": true,
         "group": "Mesh and models",
diff --git a/simpeg_drivers-assets/uijson/tdem1d_inversion.ui.json b/simpeg_drivers-assets/uijson/tdem1d_inversion.ui.json
index 95129a3d..dbefaba0 100644
--- a/simpeg_drivers-assets/uijson/tdem1d_inversion.ui.json
+++ b/simpeg_drivers-assets/uijson/tdem1d_inversion.ui.json
@@ -122,7 +122,7 @@
     "model_type": {
         "choiceList": [
             "Conductivity (S/m)",
-            "Resistivity (ohm-m)"
+            "Resistivity (Ohm-m)"
         ],
         "main": true,
         "group": "Mesh and models",
diff --git a/simpeg_drivers-assets/uijson/tdem_forward.ui.json b/simpeg_drivers-assets/uijson/tdem_forward.ui.json
index a5720a27..7549311d 100644
--- a/simpeg_drivers-assets/uijson/tdem_forward.ui.json
+++ b/simpeg_drivers-assets/uijson/tdem_forward.ui.json
@@ -70,7 +70,7 @@
     "model_type": {
         "choiceList": [
             "Conductivity (S/m)",
-            "Resistivity (ohm-m)"
+            "Resistivity (Ohm-m)"
         ],
         "main": true,
         "group": "Mesh and models",
diff --git a/simpeg_drivers-assets/uijson/tdem_inversion.ui.json b/simpeg_drivers-assets/uijson/tdem_inversion.ui.json
index c7b96f84..c9c22995 100644
--- a/simpeg_drivers-assets/uijson/tdem_inversion.ui.json
+++ b/simpeg_drivers-assets/uijson/tdem_inversion.ui.json
@@ -142,7 +142,7 @@
     "model_type": {
         "choiceList": [
             "Conductivity (S/m)",
-            "Resistivity (ohm-m)"
+            "Resistivity (Ohm-m)"
         ],
         "main": true,
         "group": "Mesh and models",
diff --git a/simpeg_drivers-assets/uijson/tipper_forward.ui.json b/simpeg_drivers-assets/uijson/tipper_forward.ui.json
index 7af86543..a0cd3617 100644
--- a/simpeg_drivers-assets/uijson/tipper_forward.ui.json
+++ b/simpeg_drivers-assets/uijson/tipper_forward.ui.json
@@ -54,7 +54,7 @@
     "model_type": {
         "choiceList": [
             "Conductivity (S/m)",
-            "Resistivity (ohm-m)"
+            "Resistivity (Ohm-m)"
         ],
         "main": true,
         "group": "Mesh and models",
diff --git a/simpeg_drivers-assets/uijson/tipper_inversion.ui.json b/simpeg_drivers-assets/uijson/tipper_inversion.ui.json
index eab33514..1581dab8 100644
--- a/simpeg_drivers-assets/uijson/tipper_inversion.ui.json
+++ b/simpeg_drivers-assets/uijson/tipper_inversion.ui.json
@@ -150,7 +150,7 @@
     "model_type": {
         "choiceList": [
             "Conductivity (S/m)",
-            "Resistivity (ohm-m)"
+            "Resistivity (Ohm-m)"
         ],
         "main": true,
         "group": "Mesh and models",
diff --git a/simpeg_drivers/components/factories/directives_factory.py b/simpeg_drivers/components/factories/directives_factory.py
index b4c74bdd..74304323 100644
--- a/simpeg_drivers/components/factories/directives_factory.py
+++ b/simpeg_drivers/components/factories/directives_factory.py
@@ -25,7 +25,7 @@
 from simpeg.utils.mat_utils import cartesian2amplitude_dip_azimuth
 
 from simpeg_drivers.components.factories.simpeg_factory import SimPEGFactory
-from simpeg_drivers.options import BaseInversionOptions
+from simpeg_drivers.options import BaseInversionOptions, ModelTypeEnum
 
 
 if TYPE_CHECKING:
@@ -418,7 +418,7 @@ def assemble_keyword_arguments(
                 inversion_object.permutation.T,
             ]
 
-            if self.params.models.model_type.lower() == "resistivity (ohm-m)":
+            if self.params.models.model_type == ModelTypeEnum.resistivity:
                 kwargs["transforms"].append(lambda x: 1 / x)
 
         if "1d" in self.factory_type:
diff --git a/simpeg_drivers/components/factories/source_factory.py b/simpeg_drivers/components/factories/source_factory.py
index ba1d729d..f9abbed9 100644
--- a/simpeg_drivers/components/factories/source_factory.py
+++ b/simpeg_drivers/components/factories/source_factory.py
@@ -24,6 +24,7 @@
 from geoh5py.objects import LargeLoopGroundTEMReceivers
 
 from simpeg_drivers.components.factories.simpeg_factory import SimPEGFactory
+from simpeg_drivers.options import ModelTypeEnum
 
 
 if TYPE_CHECKING:
@@ -138,7 +139,10 @@ def assemble_keyword_arguments(  # pylint: disable=arguments-differ
         if self.factory_type in ["magnetotellurics", "tipper"]:
             background = deepcopy(self.params.models.conductivity_model)
 
-            if getattr(self.params.models, "model_type", None) == "Resistivity (ohm-m)":
+            if (
+                getattr(self.params.models, "model_type", None)
+                == ModelTypeEnum.resistivity
+            ):
                 background **= -1.0
 
             kwargs["sigma_primary"] = [background]
diff --git a/simpeg_drivers/components/models.py b/simpeg_drivers/components/models.py
index 9cef58a6..32927f9b 100644
--- a/simpeg_drivers/components/models.py
+++ b/simpeg_drivers/components/models.py
@@ -24,6 +24,8 @@
     mkvc,
 )
 
+from simpeg_drivers.options import ModelTypeEnum
+
 
 if TYPE_CHECKING:
     from simpeg_drivers.driver import InversionDriver
@@ -165,7 +167,7 @@ def starting_model(self) -> np.ndarray | None:
         mstart = self._starting_model.model.copy()
 
         if mstart is not None and self.is_sigma:
-            if self.driver.params.models.model_type.lower() == "resistivity (ohm-m)":
+            if self.driver.params.models.model_type == ModelTypeEnum.resistivity:
                 mstart = 1 / mstart
 
             mstart = np.log(mstart)
@@ -221,7 +223,7 @@ def reference_model(self) -> np.ndarray | None:
         ref_model = mref.copy()
 
         if self.is_sigma:
-            if self.driver.params.models.model_type.lower() == "resistivity (ohm-m)":
+            if self.driver.params.models.model_type == ModelTypeEnum.resistivity:
                 ref_model = 1 / ref_model
 
             ref_model = np.log(ref_model)
@@ -263,7 +265,7 @@ def reference_declination(self) -> np.ndarray | None:
     def lower_bound(self) -> np.ndarray | None:
         if (
             self.is_sigma
-            and self.driver.params.models.model_type.lower() == "resistivity (ohm-m)"
+            and self.driver.params.models.model_type == ModelTypeEnum.resistivity
         ):
             bound_model = self._upper_bound.model
         else:
@@ -283,7 +285,7 @@ def lower_bound(self) -> np.ndarray | None:
         if self.is_sigma:
             is_finite = np.isfinite(lbound)
 
-            if self.driver.params.models.model_type.lower() == "resistivity (ohm-m)":
+            if self.driver.params.models.model_type == ModelTypeEnum.resistivity:
                 lbound[is_finite] = 1 / lbound[is_finite]
 
             lbound[is_finite] = np.log(lbound[is_finite])
@@ -297,7 +299,7 @@ def lower_bound(self) -> np.ndarray | None:
     def upper_bound(self) -> np.ndarray | None:
         if (
             self.is_sigma
-            and self.driver.params.models.model_type.lower() == "resistivity (ohm-m)"
+            and self.driver.params.models.model_type == ModelTypeEnum.resistivity
         ):
             bound_model = self._lower_bound.model
         else:
@@ -311,7 +313,7 @@ def upper_bound(self) -> np.ndarray | None:
         if self.is_sigma:
             is_finite = np.isfinite(ubound)
 
-            if self.driver.params.models.model_type.lower() == "resistivity (ohm-m)":
+            if self.driver.params.models.model_type == ModelTypeEnum.resistivity:
                 ubound[is_finite] = 1 / ubound[is_finite]
 
             ubound[is_finite] = np.log(ubound[is_finite])
@@ -329,7 +331,7 @@ def conductivity_model(self) -> np.ndarray | None:
         background_sigma = self._conductivity_model.model.copy()
 
         if background_sigma is not None:
-            if self.driver.params.models.model_type.lower() == "resistivity (ohm-m)":
+            if self.driver.params.models.model_type == ModelTypeEnum.resistivity:
                 background_sigma = 1 / background_sigma
 
             # Don't apply log if IP inversion
@@ -568,9 +570,8 @@ def save_model(self):
 
         model_type = self.model_type
         if (
-            model_type
-            and model_type.lower() == "conductivity_model"
-            and self.driver.params.models.model_type.lower() == "resistivity (ohm-m)"
+            model_type == "conductivity_model"
+            and self.driver.params.models.model_type == ModelTypeEnum.resistivity
         ):
             model_type = "resistivity_model"
 
@@ -589,12 +590,11 @@ def save_model(self):
 
     def edit_ndv_model(self, model):
         """Change values to NDV on models and save to workspace."""
+
         model_type = self.model_type
         if (
-            model_type
-            and model_type.lower() == "conductivity_model"
-            and getattr(self.driver.params.models, "model_type", None)
-            == "Resistivity (ohm-m)"
+            getattr(self.driver.params.models, "model_type", None)
+            == ModelTypeEnum.resistivity
         ):
             model_type = "resistivity_model"
 
diff --git a/simpeg_drivers/joint/driver.py b/simpeg_drivers/joint/driver.py
index 135d8897..de308714 100644
--- a/simpeg_drivers/joint/driver.py
+++ b/simpeg_drivers/joint/driver.py
@@ -38,6 +38,7 @@
 )
 from simpeg_drivers.driver import InversionDriver
 from simpeg_drivers.joint.options import BaseJointOptions
+from simpeg_drivers.options import ModelTypeEnum
 from simpeg_drivers.utils.utils import simpeg_group_to_driver
 
 
@@ -451,7 +452,10 @@ def _get_local_model_save_directives(
         )
 
         model_directive.label = driver.params.physical_property
-        if getattr(driver.params.models, "model_type", None) == "Resistivity (ohm-m)":
+        if (
+            getattr(driver.params.models, "model_type", None)
+            == ModelTypeEnum.resistivity
+        ):
             model_directive.label = "resistivity_model"
 
         model_directive.transforms = [wire, *model_directive.transforms]
diff --git a/simpeg_drivers/joint/joint_surveys/driver.py b/simpeg_drivers/joint/joint_surveys/driver.py
index e288c3b5..eb912c18 100644
--- a/simpeg_drivers/joint/joint_surveys/driver.py
+++ b/simpeg_drivers/joint/joint_surveys/driver.py
@@ -14,12 +14,12 @@
 from logging import getLogger
 
 import numpy as np
-from geoh5py.groups.property_group_type import GroupTypeEnum
 from geoh5py.shared.utils import fetch_active_workspace
 from simpeg import maps
 
 from simpeg_drivers.driver import InversionDriver
 from simpeg_drivers.joint.driver import BaseJointDriver
+from simpeg_drivers.options import ModelTypeEnum
 
 from .options import JointSurveysOptions
 
@@ -64,7 +64,7 @@ def validate_create_models(self):
                 model = np.exp(model)
                 if (
                     getattr(self.params.models, "model_type", None)
-                    == "Resistivity (ohm-m)"
+                    == ModelTypeEnum.resistivity
                 ):
                     model = 1.0 / model
 
diff --git a/simpeg_drivers/joint/joint_surveys/options.py b/simpeg_drivers/joint/joint_surveys/options.py
index 7e0da88b..b80a3bd4 100644
--- a/simpeg_drivers/joint/joint_surveys/options.py
+++ b/simpeg_drivers/joint/joint_surveys/options.py
@@ -14,11 +14,26 @@
 from pathlib import Path
 from typing import ClassVar
 
+from geoh5py.data import FloatData
 from pydantic import field_validator, model_validator
 
 from simpeg_drivers import assets_path
-from simpeg_drivers.joint.options import BaseJointOptions
-from simpeg_drivers.options import ConductivityModelOptions
+from simpeg_drivers.joint.options import BaseJointOptions, JointModelOptions
+from simpeg_drivers.options import ModelTypeEnum
+
+
+class JointSurveysModelOptions(JointModelOptions):
+    """
+    Joint Surveys model options.
+
+    :param model_type: The physical property type for the inversion.
+    :param starting_model: The starting model for the inversion.
+    :param reference_model: The reference model for the inversion.
+    """
+
+    model_type: ModelTypeEnum = ModelTypeEnum.conductivity
+    starting_model: float | FloatData | None = None
+    reference_model: float | FloatData | None = None
 
 
 class JointSurveysOptions(BaseJointOptions):
@@ -32,7 +47,7 @@ class JointSurveysOptions(BaseJointOptions):
     title: str = "Joint Surveys Inversion"
     inversion_type: str = "joint surveys"
 
-    models: ConductivityModelOptions
+    models: JointSurveysModelOptions
 
     @field_validator("group_a", "group_b", "group_c")
     @classmethod
diff --git a/simpeg_drivers/options.py b/simpeg_drivers/options.py
index 965edfcb..7499daef 100644
--- a/simpeg_drivers/options.py
+++ b/simpeg_drivers/options.py
@@ -11,6 +11,7 @@
 
 from __future__ import annotations
 
+from enum import Enum
 from logging import getLogger
 from pathlib import Path
 from typing import Annotated, Any, ClassVar, Literal, TypeAlias
@@ -314,14 +315,17 @@ def gradient_orientations(self) -> tuple(float, float):
         return None
 
 
+class ModelTypeEnum(str, Enum):
+    conductivity = "Conductivity (S/m)"
+    resistivity = "Resistivity (Ohm-m)"
+
+
 class ConductivityModelOptions(ModelOptions):
     """
     Options for the conductivity model used in all of EM methods.
     """
 
-    model_type: Literal["Conductivity (S/m)", "Resistivity (ohm-m)"] = (
-        "Conductivity (S/m)"
-    )
+    model_type: ModelTypeEnum = ModelTypeEnum.conductivity
     conductivity_model: float | FloatData | None = Field(
         None,
         validation_alias=AliasChoices("background_conductivity", "conductivity_model"),
diff --git a/simpeg_drivers/plate_simulation/driver.py b/simpeg_drivers/plate_simulation/driver.py
index d8752295..d3f62c59 100644
--- a/simpeg_drivers/plate_simulation/driver.py
+++ b/simpeg_drivers/plate_simulation/driver.py
@@ -21,11 +21,10 @@
 from geoh5py.groups import SimPEGGroup
 from geoh5py.objects import Octree, Points, Surface
 from geoh5py.shared.utils import fetch_active_workspace, stringify
-from geoh5py.ui_json import InputFile, monitored_directory_copy
 from grid_apps.octree_creation.driver import OctreeDriver
 
 from simpeg_drivers.driver import BaseDriver, InversionDriver
-from simpeg_drivers.options import BaseForwardOptions
+from simpeg_drivers.options import BaseForwardOptions, ModelTypeEnum
 from simpeg_drivers.plate_simulation.models.events import Anomaly, Erosion, Overburden
 from simpeg_drivers.plate_simulation.models.parametric import Plate
 from simpeg_drivers.plate_simulation.models.series import DikeSwarm, Geology
@@ -137,7 +136,9 @@ def simulation_parameters(self) -> BaseForwardOptions:
         if self._simulation_parameters is None:
             self._simulation_parameters = self.params.simulation_parameters()
             if self._simulation_parameters.physical_property == "conductivity":
-                self._simulation_parameters.models.model_type = "Resistivity (ohm-m)"
+                self._simulation_parameters.models.model_type = (
+                    ModelTypeEnum.resistivity
+                )
         return self._simulation_parameters
 
     @property
diff --git a/simpeg_drivers/utils/nested.py b/simpeg_drivers/utils/nested.py
index 719740e8..6ff3a325 100644
--- a/simpeg_drivers/utils/nested.py
+++ b/simpeg_drivers/utils/nested.py
@@ -275,7 +275,7 @@ def create_simulation(
 
     n_actives = int(actives.sum())
     if getattr(simulation, "_chiMap", None) is not None:
-        if simulation.model_type and simulation.model_type.lower() == "vector":
+        if simulation.model_type == "vector":
             kwargs["chiMap"] = maps.IdentityMap(nP=n_actives * 3)
             kwargs["model_type"] = "vector"
         else:
diff --git a/tests/run_tests/driver_2d_rotated_gradients_test.py b/tests/run_tests/driver_2d_rotated_gradients_test.py
index 7e1218ae..5d6be39f 100644
--- a/tests/run_tests/driver_2d_rotated_gradients_test.py
+++ b/tests/run_tests/driver_2d_rotated_gradients_test.py
@@ -153,7 +153,7 @@ def test_dc2d_rotated_grad_run(
             gradient_rotation=pg,
             potential_channel=potential,
             potential_uncertainty=1e-3,
-            model_type="Resistivity (ohm-m)",
+            model_type="Resistivity (Ohm-m)",
             starting_model=100.0,
             reference_model=100.0,
             s_norm=1.0,
diff --git a/tests/run_tests/driver_dc_2d_test.py b/tests/run_tests/driver_dc_2d_test.py
index 91ac277a..46e9cf64 100644
--- a/tests/run_tests/driver_dc_2d_test.py
+++ b/tests/run_tests/driver_dc_2d_test.py
@@ -113,7 +113,7 @@ def test_dc_2d_run(tmp_path: Path, max_iterations=1, pytest=True):
             data_object=potential.parent,
             potential_channel=potential,
             potential_uncertainty=1e-3,
-            model_type="Resistivity (ohm-m)",
+            model_type="Resistivity (Ohm-m)",
             starting_model=100.0,
             reference_model=100.0,
             s_norm=0.0,
diff --git a/tests/run_tests/driver_ip_2d_test.py b/tests/run_tests/driver_ip_2d_test.py
index 92eb45c3..219ea86b 100644
--- a/tests/run_tests/driver_ip_2d_test.py
+++ b/tests/run_tests/driver_ip_2d_test.py
@@ -64,7 +64,7 @@ def test_ip_2d_fwr_run(
             topography_object=components.topography,
             starting_model=components.model,
             conductivity_model=1e2,
-            model_type="Resistivity (ohm-m)",
+            model_type="Resistivity (Ohm-m)",
             line_selection=LineSelectionOptions(
                 line_object=geoh5.get_entity("line_ids")[0],
                 line_id=101,
diff --git a/tests/run_tests/driver_ip_test.py b/tests/run_tests/driver_ip_test.py
index 7ee6fcd6..6f828a41 100644
--- a/tests/run_tests/driver_ip_test.py
+++ b/tests/run_tests/driver_ip_test.py
@@ -90,7 +90,7 @@ def test_ip_3d_run(
             topography_object=topography,
             data_object=potential.parent,
             conductivity_model=1e2,
-            model_type="Resistivity (ohm-m)",
+            model_type="Resistivity (Ohm-m)",
             reference_model=1e-6,
             starting_model=1e-6,
             s_norm=0.0,
diff --git a/tests/run_tests/driver_joint_cross_gradient_test.py b/tests/run_tests/driver_joint_cross_gradient_test.py
index caba490b..6184c201 100644
--- a/tests/run_tests/driver_joint_cross_gradient_test.py
+++ b/tests/run_tests/driver_joint_cross_gradient_test.py
@@ -210,7 +210,7 @@ def test_joint_cross_gradient_inv_run(
                     topography_object=topography,
                     data_object=survey,
                     potential_channel=data,
-                    model_type="Resistivity (ohm-m)",
+                    model_type="Resistivity (Ohm-m)",
                     potential_uncertainty=5e-4,
                     tile_spatial=1,
                     starting_model=100.0,
diff --git a/tests/run_tests/driver_joint_surveys_test.py b/tests/run_tests/driver_joint_surveys_test.py
index 412a8da7..29537085 100644
--- a/tests/run_tests/driver_joint_surveys_test.py
+++ b/tests/run_tests/driver_joint_surveys_test.py
@@ -225,7 +225,7 @@ def test_joint_surveys_conductivity_run(
             data_object=components.survey,
             starting_model=components.model,
             reference_model=5.0,
-            model_type="Resistivity (ohm-m)",
+            model_type="Resistivity (Ohm-m)",
         )
         driver_A = DC3DInversionDriver(params)
         driver_B = DC3DInversionDriver(params)
diff --git a/tests/run_tests/driver_mt_test.py b/tests/run_tests/driver_mt_test.py
index 70736a68..45c7f2fe 100644
--- a/tests/run_tests/driver_mt_test.py
+++ b/tests/run_tests/driver_mt_test.py
@@ -169,7 +169,7 @@ def test_magnetotellurics_run(tmp_path: Path, max_iterations=1, pytest=True):
             z_norm=1.0,
             cooling_rate=1,
             lower_bound=0.75,
-            model_type="Resistivity (ohm-m)",
+            model_type="Resistivity (Ohm-m)",
             background_conductivity=100.0,
             max_global_iterations=max_iterations,
             initial_beta_ratio=1e3,
diff --git a/tests/run_tests/driver_tipper_test.py b/tests/run_tests/driver_tipper_test.py
index 72786d8c..fd34ff46 100644
--- a/tests/run_tests/driver_tipper_test.py
+++ b/tests/run_tests/driver_tipper_test.py
@@ -66,7 +66,7 @@ def test_tipper_fwr_run(
             topography_object=components.topography,
             data_object=components.survey,
             starting_model=components.model,
-            model_type="Resistivity (ohm-m)",
+            model_type="Resistivity (Ohm-m)",
             background_conductivity=1e2,
             txz_real_channel_bool=True,
             txz_imag_channel_bool=True,
@@ -146,7 +146,7 @@ def test_tipper_run(tmp_path: Path, max_iterations=1, pytest=True):
             y_norm=1.0,
             z_norm=1.0,
             alpha_s=1.0,
-            model_type="Resistivity (ohm-m)",
+            model_type="Resistivity (Ohm-m)",
             lower_bound=0.75,
             max_global_iterations=max_iterations,
             initial_beta_ratio=1e3,