A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6150-01-276-2427
NSN 5996-01-325-0197
NSN 5920-00-575-8826
NSN 6130-01-033-1536
NSN 6110-00-218-0967
NSN 5915-01-123-8292
NSN 6610-01-557-6908
NSN 6610-01-230-9971
NSN 4140-00-501-7833
NSN 5835-01-185-1102
NSN 5910-01-489-0966
NSN 6110-00-182-8664