A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 4140-01-597-0680
NSN 6650-01-446-2025
NSN 5990-01-629-7927
NSN 5910-01-532-1450
NSN 4140-01-609-8360
NSN 5998-01-531-6732
NSN 5895-00-782-0844
NSN 5915-00-229-8310
NSN 5920-01-496-8156
NSN 6320-00-468-8421
NSN 5855-01-597-4404
NSN 6150-01-004-7765