diff --git a/arraycontext/container/traversal.py b/arraycontext/container/traversal.py
index 3a11b81dccda52cd4516ddb588001e2fef415a2a..23cec03cc1c58db273eaefa5569fcdf00a3245d3 100644
--- a/arraycontext/container/traversal.py
+++ b/arraycontext/container/traversal.py
@@ -774,7 +774,7 @@ def unflatten(
 
 
 def flat_size_and_dtype(
-        ary: ArrayOrContainerT) -> Tuple[int, Optional[np.dtype[Any]]]:
+        ary: ArrayOrContainerT) -> "Tuple[int, Optional[np.dtype[Any]]]":
     """
     :returns: a tuple ``(size, dtype)`` that would be the length and
         :class:`numpy.dtype` of the one-dimensional array returned by