diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index c585724..d63cdd9 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -80,6 +80,7 @@ repos:
         files: src
         additional_dependencies:
           - plum-dispatch>=2.5.6
+          - quaxed>=0.8.1
 
   - repo: https://github.com/codespell-project/codespell
     rev: "v2.3.0"
@@ -91,11 +92,3 @@ repos:
   #   hooks:
   #     - id: validate-pyproject
   #       additional_dependencies: ["validate-pyproject-schema-store[all]"]
-
-  - repo: local
-    hooks:
-      - id: disallow-caps
-        name: Disallow improper capitalization
-        language: pygrep
-        entry: PyBind|Numpy|Cmake|CCache|Github|PyTest
-        exclude: .pre-commit-config.yaml
diff --git a/pyproject.toml b/pyproject.toml
index 547e7d3..da888de 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -36,7 +36,7 @@
     "optional-dependencies>=0.3.2",
     "plum-dispatch>=2.5.6",
     "quax>=0.0.5",
-    "quaxed>=0.7.1",
+    "quaxed>=0.8.1",
     "xmmutablemap>=0.1",
     "zeroth>=1.0.0",
 ]
diff --git a/src/unxt/_src/experimental.py b/src/unxt/_src/experimental.py
index 0a6c524..1a4a468 100644
--- a/src/unxt/_src/experimental.py
+++ b/src/unxt/_src/experimental.py
@@ -24,19 +24,20 @@
 
 from collections.abc import Callable
 from functools import partial
-from typing import Any, ParamSpec, TypeVar
+from typing import Any, TypeVar, TypeVarTuple
+from typing_extensions import Unpack
 
 import equinox as eqx
 import jax
 from jaxtyping import ArrayLike
 from plum.parametric import type_unparametrized
 
-from .quantity import Quantity, ustrip
+from .quantity import AbstractQuantity, UncheckedQuantity as FastQ, ustrip
 from .typing_ext import Unit
 from .units import unit, unit_of
 
-P = ParamSpec("P")
-R = TypeVar("R", bound=Quantity)
+Args = TypeVarTuple("Args")
+R = TypeVar("R", bound=AbstractQuantity)
 
 
 def unit_or_none(obj: Any) -> Unit | None:
@@ -44,8 +45,8 @@ def unit_or_none(obj: Any) -> Unit | None:
 
 
 def grad(
-    fun: Callable[P, R], argnums: int = 0, *, units: tuple[Unit | str, ...]
-) -> Callable[P, R]:
+    fun: Callable[[Unpack[Args]], R], argnums: int = 0, *, units: tuple[Unit | str, ...]
+) -> Callable[[Unpack[Args]], R]:
     """Gradient of a function with units.
 
     In general, if you can use ``quax.quaxify(jax.grad(func))`` (or the
@@ -76,22 +77,22 @@ def grad(
 
     # Gradient of function, stripping and adding units
     @partial(jax.grad, argnums=argnums)
-    def gradfun_mag(*args: P.args) -> ArrayLike:
+    def gradfun_mag(*args: Any) -> ArrayLike:
         args_ = (
-            (a if unit is None else Quantity(a, unit))
+            (a if unit is None else FastQ(a, unit))
             for a, unit in zip(args, theunits, strict=True)
         )
-        return ustrip(fun(*args_))  # type: ignore[call-arg]
+        return ustrip(fun(*args_))  # type: ignore[arg-type]
 
-    def gradfun(*args: P.args, **kw: P.kwargs) -> R:
+    def gradfun(*args: Unpack[Args]) -> R:
         # Get the value of the args. They are turned back into Quantity
         # inside the function we are taking the grad of.
-        args_ = tuple(
+        args_ = tuple(  # type: ignore[var-annotated]
             (a if unit is None else ustrip(unit, a))
-            for a, unit in zip(args, theunits, strict=True)
+            for a, unit in zip(args, theunits, strict=True)  # type: ignore[arg-type]
         )
         # Call the grad, returning a Quantity
-        value = fun(*args)  # type: ignore[call-arg]
+        value = fun(*args)
         grad_value = gradfun_mag(*args_)
         # Adjust the Quantity by the units of the derivative
         # TODO: get Quantity[unit] / unit2 -> Quantity[unit/unit2] working
@@ -103,8 +104,8 @@ def gradfun(*args: P.args, **kw: P.kwargs) -> R:
 
 
 def jacfwd(
-    fun: Callable[P, R], argnums: int = 0, *, units: tuple[Unit | str, ...]
-) -> Callable[P, R]:
+    fun: Callable[[Unpack[Args]], R], argnums: int = 0, *, units: tuple[Unit | str, ...]
+) -> Callable[[Unpack[Args]], R]:
     """Jacobian of ``fun`` evaluated column-by-column using forward-mode AD.
 
     In general, if you can use `quax.quaxify(jax.jacfwd(func))` (or the
@@ -128,7 +129,7 @@ def jacfwd(
 
     >>> jacfwd_cubbe_volume = u.experimental.jacfwd(cubbe_volume, units=("m",))
     >>> jacfwd_cubbe_volume(u.Quantity(2.0, "m"))
-    Quantity['area'](Array(12., dtype=float32, weak_type=True), unit='m2')
+    UncheckedQuantity(Array(12., dtype=float32, weak_type=True), unit='m2')
 
     """
     argnums = eqx.error_if(
@@ -140,19 +141,19 @@ def jacfwd(
     theunits: tuple[Unit | None, ...] = tuple(map(unit_or_none, units))
 
     @partial(jax.jacfwd, argnums=argnums)
-    def jacfun_mag(*args: P.args) -> R:
-        args_ = (
-            (a if unit is None else Quantity(a, unit))
+    def jacfun_mag(*args: Any) -> R:
+        args_ = tuple(
+            (a if unit is None else FastQ(a, unit))
             for a, unit in zip(args, theunits, strict=True)
         )
-        return fun(*args_)  # type: ignore[call-arg]
+        return fun(*args_)  # type: ignore[arg-type]
 
-    def jacfun(*args: P.args, **kw: P.kwargs) -> R:
+    def jacfun(*args: Unpack[Args]) -> R:
         # Get the value of the args. They are turned back into Quantity
         # inside the function we are taking the Jacobian of.
-        args_ = tuple(
+        args_ = tuple(  # type: ignore[var-annotated]
             (a if unit is None else ustrip(unit, a))
-            for a, unit in zip(args, theunits, strict=True)
+            for a, unit in zip(args, theunits, strict=True)  # type: ignore[arg-type]
         )
         # Call the Jacobian, returning a Quantity
         value = jacfun_mag(*args_)
@@ -167,8 +168,8 @@ def jacfun(*args: P.args, **kw: P.kwargs) -> R:
 
 
 def hessian(
-    fun: Callable[P, R], argnums: int = 0, *, units: tuple[Unit | str, ...]
-) -> Callable[P, R]:
+    fun: Callable[[Unpack[Args]], R], argnums: int = 0, *, units: tuple[Unit | str, ...]
+) -> Callable[[Unpack[Args]], R]:
     """Hessian.
 
     In general, if you can use `quax.quaxify(jax.hessian(func))` (or the
@@ -192,25 +193,25 @@ def hessian(
 
     >>> hessian_cubbe_volume = u.experimental.hessian(cubbe_volume, units=("m",))
     >>> hessian_cubbe_volume(u.Quantity(2.0, "m"))
-    Quantity['length'](Array(12., dtype=float32, weak_type=True), unit='m')
+    UncheckedQuantity(Array(12., dtype=float32, weak_type=True), unit='m')
 
     """
     theunits: tuple[Unit, ...] = tuple(map(unit_or_none, units))
 
     @partial(jax.hessian)
-    def hessfun_mag(*args: P.args) -> R:
-        args_ = (
-            (a if unit is None else Quantity(a, unit))
+    def hessfun_mag(*args: Any) -> R:
+        args_ = tuple(
+            (a if unit is None else FastQ(a, unit))
             for a, unit in zip(args, theunits, strict=True)
         )
-        return fun(*args_)  # type: ignore[call-arg]
+        return fun(*args_)  # type: ignore[arg-type]
 
-    def hessfun(*args: P.args, **kw: P.kwargs) -> R:
+    def hessfun(*args: Unpack[Args]) -> R:
         # Get the value of the args. They are turned back into Quantity
         # inside the function we are taking the hessian of.
-        args_ = tuple(
+        args_ = tuple(  # type: ignore[var-annotated]
             (a if unit is None else ustrip(unit, a))
-            for a, unit in zip(args, units, strict=True)
+            for a, unit in zip(args, units, strict=True)  # type: ignore[arg-type]
         )
         # Call the hessian, returning a Quantity
         value = hessfun_mag(*args_)
diff --git a/src/unxt/_src/quantity/base.py b/src/unxt/_src/quantity/base.py
index 876a714..f6cabd3 100644
--- a/src/unxt/_src/quantity/base.py
+++ b/src/unxt/_src/quantity/base.py
@@ -7,19 +7,20 @@
 from functools import partial
 from types import ModuleType
 from typing import TYPE_CHECKING, Any, ClassVar, NoReturn, TypeAlias, TypeVar
+from typing_extensions import override
 
 import equinox as eqx
 import jax
 import jax.core
 from astropy.units import UnitConversionError
 from jax._src.numpy.array_methods import _IndexUpdateHelper, _IndexUpdateRef
-from jaxtyping import Array, ArrayLike, ScalarLike, Shaped
+from jaxtyping import Array, ArrayLike, Bool, ScalarLike, Shaped
 from plum import add_promotion_rule, dispatch
 from quax import ArrayValue
 
 import quaxed.numpy as jnp
-import quaxed.operator as qoperator
-from dataclassish import fields, replace
+from dataclassish import replace
+from quaxed.experimental import arrayish
 
 from .api import is_unit_convertible, uconvert, ustrip
 from .mixins import AstropyQuantityCompatMixin, IPythonReprMixin, NumPyCompatMixin
@@ -55,7 +56,16 @@ class AbstractQuantity(
     AstropyQuantityCompatMixin,
     NumPyCompatMixin,
     IPythonReprMixin,
-    ArrayValue,  # type: ignore[misc]
+    ArrayValue,
+    arrayish.NumpyBinaryOpsMixin[Any, "AbstractQuantity"],
+    arrayish.NumpyComparisonMixin[Any, Bool[Array, "*shape"]],  # TODO: shape hint
+    arrayish.NumpyUnaryMixin["AbstractQuantity"],
+    arrayish.NumpyRoundMixin["AbstractQuantity"],
+    arrayish.NumpyTruncMixin["AbstractQuantity"],
+    arrayish.NumpyFloorMixin["AbstractQuantity"],
+    arrayish.NumpyCeilMixin["AbstractQuantity"],
+    arrayish.LaxLenMixin,
+    arrayish.LaxLengthHintMixin,
 ):
     """Represents an array, with each axis bound to a name.
 
@@ -175,7 +185,7 @@ def materialise(self) -> NoReturn:
         raise RuntimeError(msg)
 
     def aval(self) -> jax.core.ShapedArray:
-        return jax.core.get_aval(self.value)
+        return jax.core.get_aval(self.value)  # type: ignore[no-untyped-call]
 
     def enable_materialise(self, _: bool = True) -> "Self":  # noqa: FBT001, FBT002
         return replace(self, value=self.value, unit=self.unit)
@@ -289,47 +299,6 @@ def T(self) -> "AbstractQuantity":  # noqa: N802
     # ---------------------------------------------------------------
     # arithmetic operators
 
-    def __pos__(self) -> "AbstractQuantity":
-        """Return the value of the array.
-
-        Examples
-        --------
-        >>> import unxt as u
-        >>> q = u.Quantity(1, "m")
-        >>> +q
-        Quantity['length'](Array(1, dtype=int32, ...), unit='m')
-
-        """
-        return replace(self, value=+self.value)  # pylint: disable=E1130
-
-    def __neg__(self) -> "AbstractQuantity":
-        """Negate the value of the array.
-
-        Examples
-        --------
-        >>> import unxt as u
-        >>> q = u.Quantity(1, "m")
-        >>> -q
-        Quantity['length'](Array(-1, dtype=int32, ...), unit='m')
-
-        """
-        return replace(self, value=-self.value)  # pylint: disable=E1130
-
-    __add__ = qoperator.add
-    __radd__ = _flip_binop(qoperator.add)
-
-    __sub__ = qoperator.sub
-    __rsub__ = _flip_binop(qoperator.sub)
-
-    __mul__ = qoperator.mul
-    __rmul__ = _flip_binop(qoperator.mul)
-
-    __truediv__ = qoperator.truediv
-    __rtruediv__ = _flip_binop(qoperator.truediv)
-
-    __floordiv__ = qoperator.floordiv
-    __rfloordiv__ = _flip_binop(qoperator.floordiv)
-
     @dispatch
     def __mod__(self: "AbstractQuantity", other: Any) -> "AbstractQuantity":
         """Take the modulus.
@@ -363,46 +332,12 @@ def __rmod__(self, other: Any) -> Any:
         """
         return self % other
 
-    __pow__ = qoperator.pow
-    __rpow__ = _flip_binop(qoperator.pow)
-
-    # ---------------------------------------------------------------
-    # array operators
-
-    __matmul__ = qoperator.matmul
-    __rmatmul__ = _flip_binop(qoperator.matmul)
-
-    # ---------------------------------------------------------------
-    # bitwise operators
-    # TODO: handle edge cases, e.g. boolean Quantity, not in Astropy
-
-    # __invert__ = qoperator.invert
-    # __and__ = qoperator.and_
-    # __rand__ = _flip_binop(qoperator.and_)
-    # __or__ = qoperator.or_
-    # __ror__ = _flip_binop(qoperator.or_)
-    # __xor__ = qoperator.xor
-    # __rxor__ = _flip_binop(qoperator.xor)
-    # __lshift__ = qoperator.lshift
-    # __rlshift__ = _flip_binop(qoperator.lshift)
-    # __rshift__ = qoperator.rshift
-    # __rrshift__ = _flip_binop(qoperator.rshift)
-
-    # ---------------------------------------------------------------
-    # comparison operators
-
-    __lt__ = bool_op(jnp.less)
-    __le__ = bool_op(jnp.less_equal)
-    __eq__ = bool_op(jnp.equal)
-    __ge__ = bool_op(jnp.greater_equal)
-    __gt__ = bool_op(jnp.greater)
-    __ne__ = bool_op(jnp.not_equal)
+    # required to override mixin methods
+    __eq__ = arrayish.NumpyEqMixin.__eq__
 
     # ---------------------------------------------------------------
     # methods
 
-    __abs__ = qoperator.abs
-
     def __bool__(self) -> bool:
         """Convert a zero-dimensional array to a Python bool object.
 
@@ -538,29 +473,6 @@ def __iter__(self) -> Any:
         """
         yield from (self[i] for i in range(len(self.value)))
 
-    def __len__(self) -> int:
-        """Return the length of the array.
-
-        Examples
-        --------
-        >>> import unxt as u
-
-        Length of an unsized array:
-
-        >>> try:
-        ...     len(u.Quantity(1, "m"))
-        ... except TypeError as e:
-        ...     print(e)
-        len() of unsized object
-
-        Length of a sized array:
-
-        >>> len(u.Quantity([1, 2, 3], "m"))
-        3
-
-        """
-        return len(self.value)
-
     def argmax(self, *args: Any, **kwargs: Any) -> Array:
         """Return the indices of the maximum value.
 
@@ -605,7 +517,7 @@ def astype(self, *args: Any, **kwargs: Any) -> "AbstractQuantity":
 
     @partial(property, doc=jax.Array.at.__doc__)
     def at(self) -> "_QuantityIndexUpdateHelper":
-        return _QuantityIndexUpdateHelper(self)
+        return _QuantityIndexUpdateHelper(self)  # type: ignore[no-untyped-call]
 
     def block_until_ready(self) -> "AbstractQuantity":
         """Block until the array is ready.
@@ -757,25 +669,6 @@ def squeeze(self, *args: Any, **kwargs: Any) -> "AbstractQuantity":
     # ===============================================================
     # Python stuff
 
-    def __hash__(self) -> int:
-        """Hash the object as the tuple of its field values.
-
-        This raises a `TypeError` if the object is unhashable,
-        which JAX arrays are.
-
-        Examples
-        --------
-        >>> import unxt as u
-        >>> q1 = u.Quantity(1, "m")
-        >>> try:
-        ...     hash(q1)
-        ... except TypeError as e:
-        ...     print(e)
-        unhashable type: ...
-
-        """
-        return hash(tuple(getattr(self, f.name) for f in fields(self)))
-
     def __repr__(self) -> str:
         return f"{type(self).__name__}({self.value!r}, unit={self.unit.to_string()!r})"
 
@@ -976,9 +869,9 @@ def from_(
 # runtime-checkable type annotation in `AbstractQuantity.at`.
 # `_QuantityIndexUpdateRef` is defined after `AbstractQuantity` because it
 # references `AbstractQuantity` in its runtime-checkable type annotations.
-class _QuantityIndexUpdateHelper(_IndexUpdateHelper):  # type: ignore[misc]
+class _QuantityIndexUpdateHelper(_IndexUpdateHelper):
     def __getitem__(self, index: Any) -> "_IndexUpdateRef":
-        return _QuantityIndexUpdateRef(self.array, index)
+        return _QuantityIndexUpdateRef(self.array, index)  # type: ignore[no-untyped-call]
 
     def __repr__(self) -> str:
         """Return a string representation of the object.
@@ -994,14 +887,15 @@ def __repr__(self) -> str:
         return f"_QuantityIndexUpdateHelper({self.array!r})"
 
 
-class _QuantityIndexUpdateRef(_IndexUpdateRef):  # type: ignore[misc]
+class _QuantityIndexUpdateRef(_IndexUpdateRef):
     # This is a subclass of `_IndexUpdateRef` that is used to implement the `at`
     # attribute of `AbstractQuantity`. See also `_QuantityIndexUpdateHelper`.
 
     def __repr__(self) -> str:
         return super().__repr__().replace("_IndexUpdateRef", "_QuantityIndexUpdateRef")
 
-    def get(
+    @override
+    def get(  # type: ignore[override]
         self,
         *,
         indices_are_sorted: bool = False,
diff --git a/src/unxt/_src/quantity/mixins.py b/src/unxt/_src/quantity/mixins.py
index 348e768..65a93c4 100644
--- a/src/unxt/_src/quantity/mixins.py
+++ b/src/unxt/_src/quantity/mixins.py
@@ -157,7 +157,7 @@ def _repr_html_(self) -> str:
 
         """
         unit_repr = getattr(self.unit, "_repr_html_", self.unit.__repr__)()
-        value_repr = np.array2string(self.value, separator=", ")
+        value_repr = np.array2string(self.value, separator=", ")  # type: ignore[arg-type]
 
         return f"<span>{value_repr}</span> * <span>{unit_repr}</span>"
 
@@ -174,7 +174,7 @@ def _repr_latex_(self) -> str:
 
         """
         unit_repr = getattr(self.unit, "_repr_latex_", self.unit.__repr__)()
-        value_repr = np.array2string(self.value, separator=",~")
+        value_repr = np.array2string(self.value, separator=",~")  # type: ignore[arg-type]
 
         return f"${value_repr} \\; {unit_repr[1:-1]}$"
 
diff --git a/src/unxt/_src/quantity/register_primitives.py b/src/unxt/_src/quantity/register_primitives.py
index 5f25a50..8722a02 100644
--- a/src/unxt/_src/quantity/register_primitives.py
+++ b/src/unxt/_src/quantity/register_primitives.py
@@ -3,7 +3,7 @@
 
 __all__: list[str] = []
 
-from collections.abc import Callable, Sequence
+from collections.abc import Sequence
 from dataclasses import replace
 from math import prod
 from typing import Any, TypeAlias, TypeVar
@@ -17,11 +17,10 @@
 )
 from jax import lax, numpy as jnp
 from jax._src.ad_util import add_any_p
-from jax.core import Primitive
 from jaxtyping import Array, ArrayLike
 from plum import promote
 from plum.parametric import type_unparametrized as type_np
-from quax import register as register_
+from quax import register
 
 from quaxed import lax as qlax
 
@@ -37,11 +36,6 @@
 Axes: TypeAlias = tuple[int, ...]
 
 
-def register(primitive: Primitive, **kwargs: Any) -> Callable[[T], T]:
-    """`quax.register`, but makes mypy happy."""
-    return register_(primitive, **kwargs)
-
-
 def _to_value_rad_or_one(q: AbstractQuantity) -> ArrayLike:
     return ustrip(radian if is_unit_convertible(q.unit, radian) else one, q)
 
@@ -334,7 +328,7 @@ def _add_any_p(
     Quantity['length'](Array(1.5, dtype=float32, ...), unit='km')
 
     """
-    return replace(x, value=add_any_p.bind(ustrip(x), ustrip(y)))
+    return replace(x, value=add_any_p.bind(ustrip(x), ustrip(y)))  # type: ignore[no-untyped-call]
 
 
 # ==============================================================================
@@ -1078,9 +1072,7 @@ def _cond_p_vq(
     >>> from unxt import Quantity
 
     """
-    # print(branches)
-    # raise AttributeError
-    return lax.cond_p.bind(index, ustrip(consts), branches=branches)
+    return lax.cond_p.bind(index, ustrip(consts), branches=branches)  # type: ignore[no-untyped-call]
 
 
 # ==============================================================================
@@ -1119,7 +1111,8 @@ def _convert_element_type_p(
     """Convert the element type of a quantity."""
     # TODO: examples
     return replace(
-        operand, value=lax.convert_element_type_p.bind(ustrip(operand), **kwargs)
+        operand,
+        value=lax.convert_element_type_p.bind(ustrip(operand), **kwargs),  # type: ignore[no-untyped-call]
     )
 
 
@@ -1146,7 +1139,7 @@ def _copy_p(x: AbstractQuantity) -> AbstractQuantity:
     Quantity['length'](Array(1, dtype=int32, ...), unit='m')
 
     """
-    return replace(x, value=lax.copy_p.bind(ustrip(x)))
+    return replace(x, value=lax.copy_p.bind(ustrip(x)))  # type: ignore[no-untyped-call]
 
 
 # ==============================================================================
@@ -1408,7 +1401,7 @@ def _device_put_p(x: AbstractQuantity, **kwargs: Any) -> AbstractQuantity:
     Quantity['length'](Array(1, dtype=int32, ...), unit='m')
 
     """
-    return jt.map(lambda y: lax.device_put_p.bind(y, **kwargs), x)
+    return jt.map(lambda y: lax.device_put_p.bind(y, **kwargs), x)  # type: ignore[no-untyped-call]
 
 
 # ==============================================================================
@@ -1865,7 +1858,7 @@ def _exp2_p(x: AbstractQuantity) -> AbstractQuantity:
     Quantity['dimensionless'](Array(8., dtype=float32, ...), unit='')
 
     """
-    return replace(x, value=qlax.exp2(ustrip(one, x)))
+    return replace(x, value=qlax.exp2(ustrip(one, x)))  # type: ignore[attr-defined]
 
 
 # ==============================================================================
@@ -3110,6 +3103,30 @@ def _neg_p(x: AbstractQuantity) -> AbstractQuantity:
     return replace(x, value=qlax.neg(ustrip(x)))
 
 
+# =============================================================================
+
+
+@register(lax.not_p)
+def _not_p(x: AbstractQuantity) -> AbstractQuantity:
+    """Logical negation of a quantity.
+
+    Examples
+    --------
+    >>> from unxt.quantity import UncheckedQuantity
+
+    >>> q = UncheckedQuantity(1, "")
+    >>> ~q
+    UncheckedQuantity(Array(-2, dtype=int32, weak_type=True), unit='')
+
+    >>> from unxt.quantity import Quantity
+    >>> q = Quantity(1, "")
+    >>> ~q
+    Quantity['dimensionless'](Array(-2, dtype=int32, weak_type=True), unit='')
+
+    """
+    return replace(x, value=qlax.bitwise_not(ustrip(one, x)))
+
+
 # ==============================================================================
 
 
@@ -3437,7 +3454,7 @@ def _scan_p(
     u = unit_of(arg0)
     arg0_ = ustrip(u, arg0)
     arg1_ = ustrip(u, arg1)
-    return lax.scan_p.bind(arg0_, arg1_, *args, **kwargs)
+    return lax.scan_p.bind(arg0_, arg1_, *args, **kwargs)  # type: ignore[no-untyped-call]
 
 
 # ==============================================================================
@@ -3596,7 +3613,7 @@ def _select_n_p_jqq(which: ArrayLike, *cases: AbstractQuantity) -> AbstractQuant
     dtypes = tuple(case.dtype for case in cases)
     casesv = promote_dtypes_if_needed(dtypes, *(ustrip(u, case) for case in cases))
 
-    return replace(cases[0], value=qlax.select_n(which, *casesv))
+    return replace(cases[0], value=qlax.select_n(which, *casesv))  # type: ignore[arg-type]
 
 
 # ==============================================================================
@@ -3719,7 +3736,7 @@ def _sort_p_two_operands(
     is_stable: bool,
     num_keys: int,
 ) -> tuple[AbstractQuantity, ArrayLike]:
-    out0, out1 = lax.sort_p.bind(
+    out0, out1 = lax.sort_p.bind(  # type: ignore[no-untyped-call]
         ustrip(operand0),
         operand1,
         dimension=dimension,
@@ -3734,7 +3751,7 @@ def _sort_p_two_operands(
 def _sort_p_one_operand(
     operand: AbstractQuantity, *, dimension: int, is_stable: bool, num_keys: int
 ) -> tuple[AbstractQuantity]:
-    (out,) = lax.sort_p.bind(
+    (out,) = lax.sort_p.bind(  # type: ignore[no-untyped-call]
         ustrip(operand), dimension=dimension, is_stable=is_stable, num_keys=num_keys
     )
     return (type_np(operand)(out, unit=operand.unit),)
diff --git a/src/unxt/_src/utils.py b/src/unxt/_src/utils.py
index ccb0133..08b7336 100644
--- a/src/unxt/_src/utils.py
+++ b/src/unxt/_src/utils.py
@@ -50,7 +50,9 @@ def __new__(cls, /, *_: Any, **__: Any) -> "Self":
 class HasDType(Protocol):
     """Protocol for objects that have a dtype attribute."""
 
-    dtype: DType
+    @property
+    def dtype(self) -> DType:
+        """The dtype of the object."""
 
 
 def promote_dtypes(*arrays: HasDType) -> tuple[HasDType, ...]:
@@ -77,7 +79,7 @@ def promote_dtypes(*arrays: HasDType) -> tuple[HasDType, ...]:
     """
     common_dtype = dtypes.result_type(*arrays)
     # TODO: check if this copies.
-    return tuple(qlax.convert_element_type(arr, common_dtype) for arr in arrays)
+    return tuple(qlax.convert_element_type(arr, common_dtype) for arr in arrays)  # type: ignore[arg-type]
 
 
 def promote_dtypes_if_needed(
diff --git a/tests/unit/test_quantity.py b/tests/unit/test_quantity.py
index 57e76c1..fa72ed1 100644
--- a/tests/unit/test_quantity.py
+++ b/tests/unit/test_quantity.py
@@ -138,9 +138,14 @@ def test_getitem():
 
 def test_len():
     """Test the ``len(Quantity)`` method."""
+    # Length 3
     q = u.Quantity([1, 2, 3], "m")
     assert len(q) == 3
 
+    # Scalar
+    q = u.Quantity(1, "m")
+    assert len(q) == 0
+
 
 @pytest.mark.skip("TODO")
 def test_add():
diff --git a/uv.lock b/uv.lock
index 15bb138..41d26e7 100644
--- a/uv.lock
+++ b/uv.lock
@@ -1541,6 +1541,18 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/a1/45/582749493b8eddd0933b2d8de39b2f0cda20b3475a9d16b2447a804fd6b3/optional_dependencies-0.3.2-py3-none-any.whl", hash = "sha256:e377389e9db9d54e42b04319ba71cdd256dde561ad8d4e89cbb5847d1f8bae3f", size = 8506 },
 ]
 
+[[package]]
+name = "optype"
+version = "0.8.0"
+source = { registry = "https://pypi.org/simple" }
+dependencies = [
+    { name = "typing-extensions", marker = "python_full_version < '3.13' or (extra == 'extra-4-unxt-cpu' and extra == 'extra-4-unxt-cuda') or (extra == 'extra-4-unxt-cpu' and extra == 'extra-4-unxt-cuda12') or (extra == 'extra-4-unxt-cpu' and extra == 'extra-4-unxt-cuda12-local') or (extra == 'extra-4-unxt-cpu' and extra == 'extra-4-unxt-k8s') or (extra == 'extra-4-unxt-cpu' and extra == 'extra-4-unxt-rocm') or (extra == 'extra-4-unxt-cuda' and extra == 'extra-4-unxt-cuda12') or (extra == 'extra-4-unxt-cuda' and extra == 'extra-4-unxt-cuda12-local') or (extra == 'extra-4-unxt-cuda' and extra == 'extra-4-unxt-k8s') or (extra == 'extra-4-unxt-cuda' and extra == 'extra-4-unxt-rocm') or (extra == 'extra-4-unxt-cuda12' and extra == 'extra-4-unxt-cuda12-local') or (extra == 'extra-4-unxt-cuda12' and extra == 'extra-4-unxt-k8s') or (extra == 'extra-4-unxt-cuda12' and extra == 'extra-4-unxt-rocm') or (extra == 'extra-4-unxt-cuda12-local' and extra == 'extra-4-unxt-k8s') or (extra == 'extra-4-unxt-cuda12-local' and extra == 'extra-4-unxt-rocm') or (extra == 'extra-4-unxt-k8s' and extra == 'extra-4-unxt-rocm')" },
+]
+sdist = { url = "https://files.pythonhosted.org/packages/89/42/543e02c72aba7ebe78adb76bbfbed1bc1314eba633ad453984948e5a5f46/optype-0.8.0.tar.gz", hash = "sha256:8cbfd452d6f06c7c70502048f38a0d5451bc601054d3a577dd09c7d6363950e1", size = 85295 }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/86/ff/604be975eb0e9fd02358cdacf496f4411db97bffc27279ce260e8f50aba4/optype-0.8.0-py3-none-any.whl", hash = "sha256:90a7760177f2e7feae379a60445fceec37b932b75a00c3d96067497573c5e84d", size = 74228 },
+]
+
 [[package]]
 name = "packaging"
 version = "24.1"
@@ -2051,18 +2063,19 @@ wheels = [
 
 [[package]]
 name = "quaxed"
-version = "0.7.1"
+version = "0.8.1"
 source = { registry = "https://pypi.org/simple" }
 dependencies = [
     { name = "jax" },
     { name = "jaxlib" },
     { name = "jaxtyping" },
+    { name = "optype" },
     { name = "plum-dispatch" },
     { name = "quax" },
 ]
-sdist = { url = "https://files.pythonhosted.org/packages/aa/c6/01e425d053ee37ae2fd2cc736aaf418088c0b71c402719d06bda768bdf83/quaxed-0.7.1.tar.gz", hash = "sha256:bbc3596be9211324c2e5045e7fd919281f1a76eab63ad0dd1c8027378b1760f9", size = 123702 }
+sdist = { url = "https://files.pythonhosted.org/packages/75/17/80c24f8f21e764f2819182eaf032d620fbdd72df56388929ac4781347d02/quaxed-0.8.1.tar.gz", hash = "sha256:3856a778360cf74f01860f6774bb699a1a49b2b73c4ec7df13dd518f144084fc", size = 131590 }
 wheels = [
-    { url = "https://files.pythonhosted.org/packages/0a/63/a28e96b31fc27edac3c62d4359b82bdcb61da978b6a891061309a5bfb422/quaxed-0.7.1-py3-none-any.whl", hash = "sha256:1e1f66f3a523ff87f0a70b69c7079d5809f23091636747d8af4a6a99fa9925ba", size = 36547 },
+    { url = "https://files.pythonhosted.org/packages/cd/54/3694e96202a6fea6b197071e4d874ebda49dca5c9eb53434f7c3310b3f06/quaxed-0.8.1-py3-none-any.whl", hash = "sha256:0ce637a7154ccaf7d045caeebb0b7d1433c1f75b6d20a233a29ea99810dbd0ba", size = 48267 },
 ]
 
 [[package]]
@@ -2614,7 +2627,7 @@ wheels = [
 
 [[package]]
 name = "unxt"
-version = "1.0.1.dev26+g1d69f30.d20250115"
+version = "1.0.1.dev27+gef1e1d6.d20250121"
 source = { editable = "." }
 dependencies = [
     { name = "astropy" },
@@ -2767,7 +2780,7 @@ requires-dist = [
     { name = "optional-dependencies", specifier = ">=0.3.2" },
     { name = "plum-dispatch", specifier = ">=2.5.6" },
     { name = "quax", specifier = ">=0.0.5" },
-    { name = "quaxed", specifier = ">=0.7.1" },
+    { name = "quaxed", specifier = ">=0.8.1" },
     { name = "xmmutablemap", specifier = ">=0.1" },
     { name = "zeroth", specifier = ">=1.0.0" },
 ]