A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5950-00-147-4303
NSN 6650-01-129-8343
NSN 4140-01-287-5429
NSN 5920-00-960-7614
NSN 5905-01-167-5184
NSN 5998-00-473-2035
NSN 6150-01-313-2530
NSN 5935-00-539-5316
NSN 4140-00-980-0467
NSN 6320-01-578-6006
NSN 5975-00-004-9431
NSN 6685-00-171-4473