A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 4140-01-056-2257
NSN 6650-00-466-1697
NSN 6645-01-586-4337
NSN 6645-00-911-2999
NSN 5996-00-452-2187
NSN 5985-01-628-3693
NSN 5920-00-478-1280
NSN 5965-00-116-5363
NSN 6150-01-520-5075
NSN 6645-01-116-3423
NSN 5996-01-232-0067
NSN 5835-00-005-7909