A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5835-01-579-5941
NSN 5930-01-359-5935
NSN 6620-01-386-5543
NSN 5965-00-841-9195
NSN 6110-01-176-6388
NSN 6130-01-099-8482
NSN 5965-01-375-5238
NSN 6220-00-149-0977
NSN 6685-00-578-5951
NSN 5920-01-394-3826
NSN 6130-01-145-5846
NSN 2925-00-808-5077