A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6320-01-233-5798
NSN 5965-00-208-4896
NSN 5930-01-652-0900
NSN 5935-01-278-4480
NSN 5915-01-517-5288
NSN 5975-01-411-6597
NSN 6150-01-564-0371
NSN 4140-00-959-4255
NSN 5990-01-482-5950
NSN 2925-00-091-6745
NSN 7035-00-371-7749
NSN 4140-01-347-7842