A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5920-01-316-8286
NSN 5999-01-535-1599
NSN 6650-00-161-4122
NSN 5998-01-419-8568
NSN 6145-00-759-6745
NSN 5930-01-021-2776
NSN 5895-01-446-6768
NSN 6645-01-358-1474
NSN 5985-00-343-3632
NSN 6220-01-367-0832
NSN 6685-00-348-6693
NSN 5855-01-603-0502