A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6610-00-169-4195
NSN 6240-01-085-6576
NSN 5945-00-787-2161
NSN 6320-01-349-2131
NSN 6320-00-224-3538
NSN 6650-01-531-1196
NSN 5998-00-982-4213
NSN 5915-01-139-5441
NSN 5965-00-275-0491
NSN 6145-00-934-0331
NSN 5920-00-445-3585
NSN 5930-01-153-2667