diff --git a/stdlib/_io.pyi b/stdlib/_io.pyi
index 2a3ae09f7..ccd47726f 100644
--- a/stdlib/_io.pyi
+++ b/stdlib/_io.pyi
@@ -86,19 +86,24 @@ class BytesIO(BufferedIOBase, _BufferedIOBase, BinaryIO):  # type: ignore[misc]
 
 class BufferedReader(BufferedIOBase, _BufferedIOBase, BinaryIO):  # type: ignore[misc]  # incompatible definitions of methods in the base classes
     raw: RawIOBase
-    def __init__(self, raw: RawIOBase, buffer_size: int = ...) -> None: ...
+    def __init__(self, raw: RawIOBase, buffer_size: int = 8192) -> None: ...
     def peek(self, size: int = 0, /) -> bytes: ...
 
 class BufferedWriter(BufferedIOBase, _BufferedIOBase, BinaryIO):  # type: ignore[misc]  # incompatible definitions of writelines in the base classes
     raw: RawIOBase
-    def __init__(self, raw: RawIOBase, buffer_size: int = ...) -> None: ...
+    def __init__(self, raw: RawIOBase, buffer_size: int = 8192) -> None: ...
     def write(self, buffer: ReadableBuffer, /) -> int: ...
 
-class BufferedRandom(BufferedReader, BufferedWriter, BufferedIOBase, _BufferedIOBase):  # type: ignore[misc]  # incompatible definitions of methods in the base classes
+class BufferedRandom(BufferedIOBase, _BufferedIOBase, BinaryIO):  # type: ignore[misc]  # incompatible definitions of methods in the base classes
+    mode: str
+    name: Any
+    raw: RawIOBase
+    def __init__(self, raw: RawIOBase, buffer_size: int = 8192) -> None: ...
     def seek(self, target: int, whence: int = 0, /) -> int: ...  # stubtest needs this
+    def peek(self, size: int = 0, /) -> bytes: ...
 
 class BufferedRWPair(BufferedIOBase, _BufferedIOBase):
-    def __init__(self, reader: RawIOBase, writer: RawIOBase, buffer_size: int = ...) -> None: ...
+    def __init__(self, reader: RawIOBase, writer: RawIOBase, buffer_size: int = 8192) -> None: ...
     def peek(self, size: int = ..., /) -> bytes: ...
 
 class _TextIOBase(_IOBase):