A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6135-01-413-4747
NSN 5930-01-442-0917
NSN 5930-01-160-3470
NSN 6645-01-323-1956
NSN 5915-01-196-1846
NSN 5915-01-409-0768
NSN 6135-01-521-0378
NSN 6135-01-497-3114
NSN 5975-00-974-3830
NSN 5915-01-234-1510
NSN 5835-01-209-6410
NSN 5975-00-189-0857