A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5915-01-484-9097
NSN 5985-01-128-9978
NSN 6150-01-143-9033
NSN 5990-01-416-0362
NSN 6220-00-052-4446
NSN 6240-01-313-4765
NSN 5895-01-423-4812
NSN 5835-01-270-7899
NSN 4140-01-460-0440
NSN 6650-01-585-6317
NSN 5835-00-617-3578
NSN 6105-01-557-0140