diff --git a/rcon/source/async_rcon.py b/rcon/source/async_rcon.py
index 160356c..4c54c90 100644
--- a/rcon/source/async_rcon.py
+++ b/rcon/source/async_rcon.py
@@ -51,7 +51,7 @@ async def rcon(
     encoding: str = "utf-8",
     frag_threshold: int = 4096,
     frag_detect_cmd: str = "",
-    timeout: int | None,
+    timeout: int | None = None,
 ) -> str:
     """Run a command asynchronously."""