A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5998-01-413-8433
NSN 4140-00-141-0132
NSN 5935-01-129-7469
NSN 5855-01-383-6860
NSN 6110-00-073-8007
NSN 5945-01-380-2645
NSN 5915-01-528-8298
NSN 5895-01-335-0668
NSN 6130-00-481-5993
NSN 6105-00-495-2981
NSN 6610-01-064-0384
NSN 5996-00-808-8707