This service window, equipped with a foldable shelf, enhances functionality by converting a regular service window into a practical, multi-purpose station. By pressing the release mechanism, the stainless steel tray unfolds to provide a convenient storage or serving platform. When the larger window is shut and the smaller one is in use, it facilitates a seamless exchange process for serving and receiving. The unfolded tray acts as a temporary counter, improving service efficiency. Additionally, the tray helps protect interior equipment from spills and is easy to clean after use.