diff --git a/exponax/_base_stepper.py b/exponax/_base_stepper.py
index 5776597..54683bf 100644
--- a/exponax/_base_stepper.py
+++ b/exponax/_base_stepper.py
@@ -159,7 +159,7 @@ def __init__(
     def _build_linear_operator(
         self,
         derivative_operator: Complex[Array, "D ... (N//2)+1"],
-    ) -> Complex[Array, "D ... (N//2)+1"]:
+    ) -> Complex[Array, "C ... (N//2)+1"]:
         """
         Assemble the L operator in Fourier space.
 
@@ -169,7 +169,7 @@ def _build_linear_operator(
               N//2+1).
 
         **Returns:**
-            - `L`: The linear operator, shape `( D, ..., N//2+1 )`.
+            - `L`: The linear operator, shape `( C, ..., N//2+1 )`.
         """
         pass