A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6650-01-501-5661
NSN 6105-01-021-8133
NSN 5855-00-466-2309
NSN 6320-01-158-2177
NSN 6130-01-209-6893
NSN 5990-00-088-7591
NSN 6620-01-610-5081
NSN 6130-01-594-0566
NSN 5835-01-238-3381
NSN 5945-00-352-5124
NSN 5935-00-534-2171
NSN 5895-01-307-5491