A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5975-01-212-2761
NSN 5965-01-494-1485
NSN 6645-01-169-3978
NSN 6105-00-253-3828
NSN 6240-00-526-0243
NSN 6145-01-417-7811
NSN 5990-01-328-0808
NSN 6135-00-269-5843
NSN 5915-01-567-8298
NSN 5975-00-183-6561
NSN 5985-00-291-9974
NSN 2925-01-052-0636