diff --git a/requests_util/__init__.py b/requests_util/__init__.py
index 3084e91..8dafd8d 100644
--- a/requests_util/__init__.py
+++ b/requests_util/__init__.py
@@ -71,7 +71,7 @@ def initialize_session() -> requests.Session:
 def setup_limiter(
     session: requests.Session,
     url_prefix: str,
-    expire_after: datetime.datetime | None = None,
+    expire_after: datetime.timedelta | None = None,
     **limiter_args,
 ) -> requests.Session:
     """Initializes limiter on session for the given domain with the given