A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5895-01-412-3844
NSN 4140-01-364-6966
NSN 6645-00-116-1409
NSN 6130-01-224-2223
NSN 5835-00-690-8898
NSN 5950-01-521-3985
NSN 5999-01-383-6984
NSN 5950-00-298-2042
NSN 6220-00-063-7661
NSN 5990-01-609-4793
NSN 5960-01-515-4791
NSN 4140-01-391-6462