A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5930-01-330-9244
NSN 6110-00-190-1260
NSN 5999-01-515-6900
NSN 5835-00-904-6272
NSN 6105-00-986-8231
NSN 6240-01-519-5089
NSN 6645-01-365-4091
NSN 5920-01-618-6973
NSN 5965-00-417-8182
NSN 4140-01-128-4939
NSN 6650-01-331-5243
NSN 6685-01-332-9680