3 files changed, 15 insertions, 13 deletions
diff --git a/pint/facets/nonmultiplicative/definitions.py b/pint/facets/nonmultiplicative/definitions.py
index dbfc0ff..f795cf0 100644
--- a/pint/facets/nonmultiplicative/definitions.py
+++ b/pint/facets/nonmultiplicative/definitions.py
@@ -10,6 +10,7 @@ from __future__ import annotations
 
 from dataclasses import dataclass
 
+from ..._typing import Magnitude
 from ...compat import HAS_NUMPY, exp, log
 from ..plain import ScaleConverter
 
@@ -24,7 +25,7 @@ class OffsetConverter(ScaleConverter):
     def is_multiplicative(self):
         return self.offset == 0
 
-    def to_reference(self, value, inplace=False):
+    def to_reference(self, value: Magnitude, inplace: bool = False) -> Magnitude:
         if inplace:
             value *= self.scale
             value += self.offset
@@ -33,7 +34,7 @@ class OffsetConverter(ScaleConverter):
 
         return value
 
-    def from_reference(self, value, inplace=False):
+    def from_reference(self, value: Magnitude, inplace: bool = False) -> Magnitude:
         if inplace:
             value -= self.offset
             value /= self.scale
@@ -66,6 +67,7 @@ class LogarithmicConverter(ScaleConverter):
         controls if computation is done in place
     """
 
+    # TODO: Can I use PintScalar here?
     logbase: float
     logfactor: float
 
@@ -77,7 +79,7 @@ class LogarithmicConverter(ScaleConverter):
     def is_logarithmic(self):
         return True
 
-    def from_reference(self, value, inplace=False):
+    def from_reference(self, value: Magnitude, inplace: bool = False) -> Magnitude:
         """Converts value from the reference unit to the logarithmic unit
 
         dBm   <------   mW
@@ -95,7 +97,7 @@ class LogarithmicConverter(ScaleConverter):
 
         return value
 
-    def to_reference(self, value, inplace=False):
+    def to_reference(self, value: Magnitude, inplace: bool = False) -> Magnitude:
         """Converts value to the reference unit from the logarithmic unit
 
         dBm   ------>   mW
diff --git a/pint/facets/nonmultiplicative/objects.py b/pint/facets/nonmultiplicative/objects.py
index 1708e32..0ab743e 100644
--- a/pint/facets/nonmultiplicative/objects.py
+++ b/pint/facets/nonmultiplicative/objects.py
@@ -8,16 +8,16 @@
 
 from __future__ import annotations
 
-from typing import List
+from ..plain import PlainQuantity
 
 
-class NonMultiplicativeQuantity:
+class NonMultiplicativeQuantity(PlainQuantity):
     @property
     def _is_multiplicative(self) -> bool:
         """Check if the PlainQuantity object has only multiplicative units."""
         return not self._get_non_multiplicative_units()
 
-    def _get_non_multiplicative_units(self) -> List[str]:
+    def _get_non_multiplicative_units(self) -> list[str]:
         """Return a list of the of non-multiplicative units of the PlainQuantity object."""
         return [
             unit
@@ -25,7 +25,7 @@ class NonMultiplicativeQuantity:
             if not self._get_unit_definition(unit).is_multiplicative
         ]
 
-    def _get_delta_units(self) -> List[str]:
+    def _get_delta_units(self) -> list[str]:
         """Return list of delta units ot the PlainQuantity object."""
         return [u for u in self._units if u.startswith("delta_")]
 
@@ -40,7 +40,7 @@ class NonMultiplicativeQuantity:
             self._get_unit_definition(d).reference == offset_unit_dim for d in deltas
         )
 
-    def _ok_for_muldiv(self, no_offset_units=None) -> bool:
+    def _ok_for_muldiv(self, no_offset_units: int | None = None) -> bool:
         """Checks if PlainQuantity object can be multiplied or divided"""
 
         is_ok = True
diff --git a/pint/facets/nonmultiplicative/registry.py b/pint/facets/nonmultiplicative/registry.py
index 17b053e..8bc04db 100644
--- a/pint/facets/nonmultiplicative/registry.py
+++ b/pint/facets/nonmultiplicative/registry.py
@@ -8,7 +8,7 @@
 
 from __future__ import annotations
 
-from typing import Any, Optional
+from typing import Any
 
 from ...errors import DimensionalityError, UndefinedUnitError
 from ...util import UnitsContainer, logger
@@ -35,7 +35,7 @@ class NonMultiplicativeRegistry(PlainRegistry):
 
     """
 
-    _quantity_class = NonMultiplicativeQuantity
+    Quantity = NonMultiplicativeQuantity
 
     def __init__(
         self,
@@ -56,8 +56,8 @@ class NonMultiplicativeRegistry(PlainRegistry):
     def _parse_units(
         self,
         input_string: str,
-        as_delta: Optional[bool] = None,
-        case_sensitive: Optional[bool] = None,
+        as_delta: bool | None = None,
+        case_sensitive: bool | None = None,
     ):
         """ """
         if as_delta is None: