A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 7035-00-445-9657
NSN 5998-01-072-8387
NSN 5960-01-030-1304
NSN 6645-01-362-2587
NSN 5905-00-277-7439
NSN 6105-01-462-3628
NSN 5835-01-453-3074
NSN 5925-00-881-9766
NSN 5925-01-158-0762
NSN 6135-00-877-1659
NSN 5960-00-275-7497
NSN 2925-01-510-2221