A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6145-00-842-4147
NSN 5920-00-412-4813
NSN 6150-01-634-0575
NSN 6620-00-706-2481
NSN 2925-01-021-7563
NSN 5960-01-649-1341
NSN 6105-01-611-3999
NSN 6110-01-659-0237
NSN 5935-01-505-0686
NSN 5935-01-193-4908
NSN 6145-00-452-4501
NSN 6135-01-189-5567