A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5998-01-485-3274
NSN 5998-01-135-5844
NSN 6220-00-379-4044
NSN 5996-01-206-0434
NSN 5990-00-269-2226
NSN 6135-00-016-0071
NSN 7035-01-154-0796
NSN 6110-00-149-8353
NSN 5990-00-023-4163
NSN 5965-01-250-3214
NSN 5998-01-178-1113
NSN 6145-01-248-1066