A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5925-00-269-2685
NSN 2925-01-053-5697
NSN 6620-00-901-4523
NSN 6135-01-069-8575
NSN 5905-01-647-2776
NSN 6145-01-452-3604
NSN 5950-01-134-1694
NSN 6130-00-179-3069
NSN 5910-00-313-2901
NSN 6240-01-101-1323
NSN 6620-01-325-6295
NSN 4140-01-375-9921