A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5835-00-187-1481
NSN 5945-00-230-7761
NSN 6320-00-643-0958
NSN 6320-00-925-0558
NSN 5935-01-089-5151
NSN 6650-01-190-2304
NSN 5985-00-285-8466
NSN 5975-00-596-4716
NSN 5920-01-484-5415
NSN 5945-01-609-4301
NSN 5999-00-964-8968
NSN 5985-00-833-9393