A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6150-01-536-5378
NSN 5855-00-165-3093
NSN 5930-01-549-3831
NSN 6150-01-518-8572
NSN 5945-01-022-9998
NSN 6650-01-297-4376
NSN 5990-01-440-7135
NSN 6685-01-416-2402
NSN 5925-00-479-8233
NSN 5985-00-518-1748
NSN 5930-01-097-7377
NSN 5920-01-655-7375