A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5930-00-531-0541
NSN 5985-01-628-7622
NSN 6650-00-246-3751
NSN 5835-01-478-0157
NSN 6610-00-200-8832
NSN 5855-01-067-8841
NSN 5910-01-340-1152
NSN 6130-01-532-6973
NSN 6135-01-100-3593
NSN 5985-00-946-3867
NSN 5999-01-012-1421
NSN 5920-00-681-5722