diff --git a/arraycontext/container/traversal.py b/arraycontext/container/traversal.py
index ed6dc0c2482290a951258862aa392096a3040c16..b2abc74071ae63eb4ed246921f2a9c9e41c93cef 100644
--- a/arraycontext/container/traversal.py
+++ b/arraycontext/container/traversal.py
@@ -142,7 +142,7 @@ def _multimap_array_container_impl(
     if len(container_indices) == 1 and reduce_func is None:
         # NOTE: if we just have one ArrayContainer in args, passing it through
         # _map_array_container_impl should be faster
-        def wrapper(ary: ContainerT) -> ContainerT:
+        def wrapper(ary: ArrayOrContainerT) -> ArrayOrContainerT:
             new_args = list(args)
             new_args[container_indices[0]] = ary
             return f(*new_args)