A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5945-01-447-2622
NSN 6150-00-551-3135
NSN 6610-01-660-3966
NSN 5895-01-194-5676
NSN 6105-00-716-2116
NSN 6650-01-495-1269
NSN 6220-00-828-5282
NSN 5996-01-607-7035
NSN 5975-01-142-2799
NSN 5905-01-103-9521
NSN 5915-01-147-2286
NSN 5960-01-503-0362