A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6105-01-334-9807
NSN 5855-00-135-0797
NSN 5998-01-358-6283
NSN 5999-01-536-7760
NSN 5855-01-483-2346
NSN 5965-00-424-9636
NSN 5965-00-468-3071
NSN 6130-01-071-5341
NSN 5950-00-969-3927
NSN 5975-01-194-2521
NSN 5998-01-007-6882
NSN 5960-00-772-2994