A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6240-01-463-7057
NSN 5910-01-633-0158
NSN 7035-01-492-3376
NSN 5945-01-398-2249
NSN 6620-01-658-1587
NSN 5975-00-137-0377
NSN 6320-00-994-0179
NSN 5920-01-182-0612
NSN 5835-00-754-7255
NSN 5965-01-548-0954
NSN 6610-01-417-6336
NSN 7035-01-252-5919