A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5835-01-264-8782
NSN 5935-01-146-4323
NSN 6620-01-333-7014
NSN 4140-01-290-1733
NSN 5925-01-634-0664
NSN 5930-00-350-8545
NSN 5996-01-165-9344
NSN 6110-01-492-0145
NSN 6620-01-519-2628
NSN 6240-01-596-7742
NSN 5835-01-580-0446
NSN 6240-01-010-9038