A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6240-01-266-9492
NSN 5996-01-096-4648
NSN 5998-01-075-1315
NSN 6145-01-486-0572
NSN 6145-00-932-5698
NSN 6240-01-175-3877
NSN 5999-00-913-1280
NSN 6650-00-336-4828
NSN 6110-01-579-4480
NSN 6320-01-098-2503
NSN 6130-01-438-6291
NSN 6150-00-137-9802