A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 4140-01-151-2158
NSN 5895-01-631-3945
NSN 6150-01-494-0237
NSN 5915-01-191-7554
NSN 5925-00-523-2755
NSN 2925-01-341-0457
NSN 6130-00-801-2712
NSN 5996-01-353-1597
NSN 5945-00-236-2737
NSN 5920-01-553-3340
NSN 5895-01-105-9264
NSN 5945-01-542-0232