A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5996-01-040-0716
NSN 5975-00-452-6206
NSN 6240-01-607-6252
NSN 6110-01-091-9364
NSN 6135-01-332-0431
NSN 5855-01-434-2825
NSN 5910-01-276-4702
NSN 6110-01-446-7482
NSN 5935-01-500-4437
NSN 6320-01-265-0665
NSN 5835-01-182-1966
NSN 6150-01-502-4619