diff --git a/stdlib/2and3/wave.pyi b/stdlib/2and3/wave.pyi
index 52bc9b156..ca76ca5e2 100644
--- a/stdlib/2and3/wave.pyi
+++ b/stdlib/2and3/wave.pyi
@@ -2,10 +2,10 @@
 
 import sys
 from typing import (
-    Any, NamedTuple, NoReturn, Optional, Text, BinaryIO, Union, Tuple
+    Any, NamedTuple, NoReturn, Optional, Text, BinaryIO, Union, Tuple, IO
 )
 
-_File = Union[Text, BinaryIO]
+_File = Union[Text, IO[bytes]]
 
 class Error(Exception): ...