This is the OEM Subaru 6-Speed Manual Transmission Secondary Drain Plug replacement Washer.
Its always a good idea to replace this when performing a transmission fluid drain & fill on your manual transmission Subaru.
The 6-Speed Manual Transmissions have a secondary drain plug to evacuate the fliud from the lowest point.
The Transmission & Front Diff are both drained from the same plug, & re-filled through the dipstick tube.
Manufacturer: Subaru
MPN: 803916080
SKU: sub803916080