A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6240-00-103-0058
NSN 5990-00-170-4239
NSN 6105-01-513-3334
NSN 5985-00-112-4612
NSN 5910-00-266-0104
NSN 5835-01-092-3595
NSN 5935-01-351-8387
NSN 6105-01-528-8027
NSN 5910-01-381-0236
NSN 5855-00-247-3403
NSN 6320-01-592-4567
NSN 5975-01-022-9713