A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 4140-01-231-9196
NSN 6240-01-550-3112
NSN 5855-00-610-4052
NSN 5905-01-384-2789
NSN 5935-01-401-5324
NSN 5996-01-252-6262
NSN 5835-01-432-1277
NSN 5895-01-494-8922
NSN 6650-01-282-2384
NSN 5998-01-286-2124
NSN 5905-00-110-0310
NSN 7035-01-438-2108