A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6150-01-095-4581
NSN 6610-00-811-6072
NSN 5985-00-387-5974
NSN 5999-01-525-8222
NSN 5998-00-507-3765
NSN 5999-00-339-3005
NSN 7035-00-225-6499
NSN 6240-00-116-7442
NSN 5945-00-231-4948
NSN 6220-01-445-0050
NSN 5835-01-051-7584
NSN 6320-00-823-2015