diff --git a/src/unxt/_quantity/base.py b/src/unxt/_quantity/base.py
index 570c6fa..45359ed 100644
--- a/src/unxt/_quantity/base.py
+++ b/src/unxt/_quantity/base.py
@@ -20,7 +20,6 @@
 )
 from jax.numpy import dtype as DType  # noqa: N812
 from jaxtyping import Array, ArrayLike, Shaped
-from plum import add_promotion_rule
 from quax import ArrayValue
 from typing_extensions import Self
 
@@ -192,6 +191,7 @@ def constructor(
     def constructor(
         cls: "type[AbstractQuantity]",
         value: ArrayLike | ArrayLikeSequence,
+        /,
         *,
         unit: Any,
         dtype: Any = None,
@@ -544,7 +544,7 @@ def constructor(
 
 @AbstractQuantity.constructor._f.register  # type: ignore[no-redef] # noqa: SLF001
 def constructor(
-    cls: type[AbstractQuantity], value: AstropyQuantity, *, dtype: Any = None
+    cls: type[AbstractQuantity], value: AstropyQuantity, /, *, dtype: Any = None
 ) -> AbstractQuantity:
     """Construct a `Quantity` from another `Quantity`.
 
@@ -572,7 +572,7 @@ def constructor(
 # -----------------------------------------------
 # Promotion rules
 
-add_promotion_rule(AbstractQuantity, AbstractQuantity, AbstractQuantity)
+# add_promotion_rule(AbstractQuantity, AbstractQuantity, AbstractQuantity)
 
 
 # ===============================================================