A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6650-00-824-0745
NSN 5945-01-237-3920
NSN 5975-01-424-8334
NSN 5999-01-494-3084
NSN 6150-01-306-6911
NSN 6135-01-400-2947
NSN 5895-01-178-4061
NSN 5975-01-064-0370
NSN 5990-01-210-9788
NSN 5915-00-753-9636
NSN 5960-00-430-3781
NSN 5998-00-873-4129