A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5930-00-449-6263
NSN 4140-01-429-8545
NSN 6220-01-485-9737
NSN 4140-01-249-7948
NSN 6105-01-146-3543
NSN 6110-01-382-5350
NSN 6650-01-534-5787
NSN 5925-00-308-7146
NSN 5835-01-123-8305
NSN 5985-01-602-0175
NSN 5935-01-026-2313
NSN 5998-01-050-7000