A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5910-01-475-8635
NSN 5925-01-466-8153
NSN 5996-00-939-1867
NSN 5935-01-256-1738
NSN 5930-01-363-9241
NSN 6240-01-126-9167
NSN 5975-00-819-1861
NSN 4140-00-218-0804
NSN 6240-01-428-9410
NSN 6220-01-392-0502
NSN 5905-01-423-2427
NSN 5855-01-136-9532