A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5895-01-644-5843
NSN 6135-01-561-5945
NSN 6105-01-273-8137
NSN 6240-01-628-9240
NSN 6110-00-331-8472
NSN 6650-01-115-7981
NSN 6150-01-500-1610
NSN 5960-01-495-0859
NSN 5965-01-633-8849
NSN 5920-01-485-9759
NSN 5895-01-354-8452
NSN 5960-01-173-7956