A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5975-01-406-0046
NSN 5998-01-123-9579
NSN 6130-00-354-0251
NSN 5950-01-462-0377
NSN 5965-01-359-8172
NSN 5855-01-294-2804
NSN 6145-01-463-3122
NSN 5925-01-025-7008
NSN 7035-00-628-3471
NSN 5999-00-193-8398
NSN 4140-01-549-4647
NSN 5930-01-149-7213