diff --git a/src/pip/_internal/operations/install/wheel.py b/src/pip/_internal/operations/install/wheel.py
index a33d6faf304..c7d9c09cc65 100644
--- a/src/pip/_internal/operations/install/wheel.py
+++ b/src/pip/_internal/operations/install/wheel.py
@@ -382,7 +382,7 @@ def save(self) -> None:
         with open(self.dest_path, "wb") as dest:
             if zipinfo.file_size > 0:
                 with self._zip_file.open(zipinfo) as f:
-                    blocksize = min(zipinfo.file_size, 1_048_576)
+                    blocksize = min(zipinfo.file_size, 1024 * 1024)
                     shutil.copyfileobj(f, dest, blocksize)
 
         if zip_item_is_executable(zipinfo):