A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6620-01-227-7219
NSN 5930-01-167-1826
NSN 6220-01-532-6880
NSN 6130-00-901-5595
NSN 5935-00-839-0728
NSN 5999-01-213-8644
NSN 4140-01-295-8264
NSN 5930-00-710-4535
NSN 6105-01-340-6582
NSN 6685-00-284-2244
NSN 6105-01-449-1046
NSN 5915-01-139-5070