diff --git a/src/galax/potential/_potential/builtin/multipole.py b/src/galax/potential/_potential/builtin/multipole.py
index 996e541b..7c71d84c 100644
--- a/src/galax/potential/_potential/builtin/multipole.py
+++ b/src/galax/potential/_potential/builtin/multipole.py
@@ -59,11 +59,13 @@ class MultipoleInnerPotential(AbstractMultipolePotential):
 
     def __check_init__(self) -> None:
         shape = (self.l_max + 1, self.l_max + 1)
-        # TODO: don't use .value
-        if self.Slm.value.shape != shape or self.Tlm.value.shape != shape:
+        t = Quantity(0.0, "Gyr")
+        s_shape, t_shape = self.Slm(t).shape, self.Tlm(t).shape
+        # TODO: check shape across time.
+        if s_shape != shape or t_shape != shape:
             msg = (
                 "Slm and Tlm must have the shape (l_max + 1, l_max + 1)."
-                f"Slm shape: {self.Slm.value.shape}, Tlm shape: {self.Tlm.value.shape}"
+                f"Slm shape: {s_shape}, Tlm shape: {t_shape}"
             )
             raise ValueError(msg)
 
@@ -115,10 +117,14 @@ class MultipoleOuterPotential(AbstractMultipolePotential):
     r"""Spherical harmonic coefficients for the $\sin(m \phi)$ terms."""
 
     def __check_init__(self) -> None:
-        shape = (self.l_max + 1, self.l_max + 1)
-        # TODO: don't use .value
-        if self.Slm.value.shape != shape or self.Tlm.value.shape != shape:
-            msg = "Slm and Tlm must have the shape (l_max + 1, l_max + 1)."
+        t = Quantity(0.0, "Gyr")
+        s_shape, t_shape = self.Slm(t).shape, self.Tlm(t).shape
+        # TODO: check shape across time.
+        if s_shape != shape or t_shape != shape:
+            msg = (
+                "Slm and Tlm must have the shape (l_max + 1, l_max + 1)."
+                f"Slm shape: {s_shape}, Tlm shape: {t_shape}"
+            )
             raise ValueError(msg)
 
     @partial(jax.jit, inline=True)
@@ -177,12 +183,15 @@ class MultipolePotential(AbstractMultipolePotential):
 
     def __check_init__(self) -> None:
         shape = (self.l_max + 1, self.l_max + 1)
-        # TODO: don't use .value
+        t = Quantity(0.0, "Gyr")
+        is_shape, it_shape = self.ISlm(t).shape, self.ITlm(t).shape
+        os_shape, ot_shape = self.OSlm(t).shape, self.OTlm(t).shape
+        # TODO: check shape across time.
         if (
-            self.ISlm.value.shape != shape
-            or self.ITlm.value.shape != shape
-            or self.OSlm.value.shape != shape
-            or self.OTlm.value.shape != shape
+            is_shape != shape
+            or it_shape != shape
+            or os_shape != shape
+            or ot_shape != shape
         ):
             msg = "I/OSlm and I/OTlm must have the shape (l_max + 1, l_max + 1)."
             raise ValueError(msg)
diff --git a/tests/unit/potential/builtin/multipole/test_innermultipole.py b/tests/unit/potential/builtin/multipole/test_innermultipole.py
index 2a4b7c7a..8d7701e5 100644
--- a/tests/unit/potential/builtin/multipole/test_innermultipole.py
+++ b/tests/unit/potential/builtin/multipole/test_innermultipole.py
@@ -57,6 +57,16 @@ def fields_(
 
     # ==========================================================================
 
+    def test_check_init(
+        self, pot_cls: type[gp.MultipoleInnerPotential], fields_: dict[str, Any]
+    ) -> None:
+        """Test the `MultipoleInnerPotential.__check_init__` method."""
+        fields_["Slm"] = fields_["Slm"][::2]  # make it the wrong shape
+        with pytest.raises(ValueError, match="Slm and Tlm must have the shape"):
+            pot_cls(**fields_)
+
+    # ==========================================================================
+
     def test_potential(self, pot: gp.MultipoleInnerPotential, x: gt.QVec3) -> None:
         expect = Quantity(32.96969177, unit="kpc2 / Myr2")
         assert qnp.isclose(
diff --git a/tests/unit/potential/builtin/multipole/test_multipole.py b/tests/unit/potential/builtin/multipole/test_multipole.py
index 9f4a0b0c..2fac103e 100644
--- a/tests/unit/potential/builtin/multipole/test_multipole.py
+++ b/tests/unit/potential/builtin/multipole/test_multipole.py
@@ -252,6 +252,16 @@ def fields_(
 
     # ==========================================================================
 
+    def test_check_init(
+        self, pot_cls: type[gp.MultipoleInnerPotential], fields_: dict[str, Any]
+    ) -> None:
+        """Test the `MultipoleInnerPotential.__check_init__` method."""
+        fields_["ISlm"] = fields_["ISlm"][::2]  # make it the wrong shape
+        with pytest.raises(ValueError, match="Slm and Tlm must have the shape"):
+            pot_cls(**fields_)
+
+    # ==========================================================================
+
     def test_potential(self, pot: gp.MultipolePotential, x: gt.QVec3) -> None:
         expect = Quantity(33.59908611, unit="kpc2 / Myr2")
         assert jnp.isclose(
diff --git a/tests/unit/potential/builtin/multipole/test_outermultipole.py b/tests/unit/potential/builtin/multipole/test_outermultipole.py
index 1e097afd..3ab3b344 100644
--- a/tests/unit/potential/builtin/multipole/test_outermultipole.py
+++ b/tests/unit/potential/builtin/multipole/test_outermultipole.py
@@ -57,6 +57,16 @@ def fields_(
 
     # ==========================================================================
 
+    def test_check_init(
+        self, pot_cls: type[gp.MultipoleInnerPotential], fields_: dict[str, Any]
+    ) -> None:
+        """Test the `MultipoleInnerPotential.__check_init__` method."""
+        fields_["Slm"] = fields_["Slm"][::2]  # make it the wrong shape
+        with pytest.raises(ValueError, match="Slm and Tlm must have the shape"):
+            pot_cls(**fields_)
+
+    # ==========================================================================
+
     def test_potential(self, pot: gp.MultipoleOuterPotential, x: gt.QVec3) -> None:
         expect = Quantity(0.62939434, unit="kpc2 / Myr2")
         assert qnp.isclose(