A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5990-01-421-3325
NSN 5945-01-487-8536
NSN 5935-01-211-7821
NSN 6145-00-370-1964
NSN 5960-00-443-1483
NSN 5905-01-088-6816
NSN 5925-01-112-2244
NSN 5998-00-597-7175
NSN 5965-01-633-8849
NSN 5985-00-644-9752
NSN 6105-00-807-8986
NSN 6130-01-416-6266