A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 2925-01-125-4800
NSN 5950-01-311-1301
NSN 6130-01-237-2358
NSN 5996-00-148-8474
NSN 6150-01-283-4355
NSN 6620-00-572-7301
NSN 5930-01-160-9446
NSN 5930-01-301-0181
NSN 5935-01-079-8612
NSN 5996-00-758-4088
NSN 6320-00-242-3300
NSN 5915-01-571-3925