A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5895-01-101-8687
NSN 6105-00-891-3035
NSN 5945-00-780-8008
NSN 5945-01-109-6334
NSN 5935-00-555-6945
NSN 5935-00-079-1308
NSN 5975-01-099-1708
NSN 6150-01-283-7945
NSN 5998-01-179-2834
NSN 5985-01-434-3061
NSN 5855-01-437-6161
NSN 6240-01-080-0888