A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5996-00-851-8428
NSN 6320-00-994-0179
NSN 6240-01-025-5847
NSN 4140-00-952-2287
NSN 5999-01-221-6968
NSN 5905-01-188-2820
NSN 4140-01-076-3720
NSN 6320-01-521-1764
NSN 5985-00-256-6897
NSN 6130-01-073-2384
NSN 6650-01-279-0658
NSN 5990-01-227-0660