A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5990-01-550-7827
NSN 5905-01-087-0141
NSN 5990-01-465-3088
NSN 5855-00-532-0025
NSN 6105-01-649-7289
NSN 5855-00-494-9581
NSN 5998-00-113-2320
NSN 2925-01-466-0892
NSN 6110-00-533-8623
NSN 6650-01-628-3453
NSN 6320-00-238-9973
NSN 6320-01-459-6992