A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5910-01-578-9401
NSN 5915-01-038-3994
NSN 6110-01-173-6221
NSN 5985-00-416-9427
NSN 6610-01-171-3010
NSN 5915-01-530-3013
NSN 6320-00-831-2227
NSN 4140-00-468-3499
NSN 5999-00-074-0544
NSN 6105-01-444-3849
NSN 5855-00-337-3679
NSN 5855-01-524-4474