diff --git a/tanjun/annotations.py b/tanjun/annotations.py
index cfb854c6b..da738289d 100644
--- a/tanjun/annotations.py
+++ b/tanjun/annotations.py
@@ -336,12 +336,12 @@ def __init__(self, converter: _ConverterSig[typing.Any], /, *other_converters: _
 
         Parameters
         ----------
-        converter : collections.abc.Callable
+        converter : collections.abc.Callable[[str], collections.Coroutine[Any, Any, Any] | Any]
             The first converter this argument should use to handle values passed to it
             during parsing.
 
             Only the first converter to pass will be used.
-        *other_converters : collections.abc.Callable
+        *other_converters : collections.abc.Callable[[str], collections.Coroutine[Any, Any, Any] | Any]
             Other first converter(s) this argument should use to handle values passed to it
             during parsing.