A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5950-00-333-3049
NSN 5960-00-246-9749
NSN 6240-00-251-5235
NSN 5975-00-552-1764
NSN 5930-01-462-2771
NSN 5998-01-537-1036
NSN 5960-01-399-4327
NSN 5930-01-023-7293
NSN 6110-01-385-8863
NSN 5960-00-990-6850
NSN 6145-01-025-9682
NSN 5855-01-652-4934