A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6610-01-067-6591
NSN 5975-01-578-0161
NSN 5910-01-475-1319
NSN 5835-00-239-9619
NSN 6240-01-182-3002
NSN 5915-01-621-3273
NSN 6220-00-936-9471
NSN 5985-01-519-1359
NSN 6145-01-422-1830
NSN 5998-01-661-0946
NSN 6105-00-413-2558
NSN 5905-01-532-3714