A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6145-00-060-0301
NSN 5965-01-544-6021
NSN 2925-01-325-2490
NSN 5998-01-338-2683
NSN 5945-00-399-0716
NSN 6610-00-072-8608
NSN 6645-01-523-8809
NSN 5835-01-197-9880
NSN 5910-00-374-5048
NSN 5950-00-975-0555
NSN 5975-00-382-0721
NSN 5945-01-575-7241