A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5999-00-463-3216
NSN 5915-01-251-3849
NSN 6650-01-090-0719
NSN 5985-01-066-0987
NSN 5835-00-221-6628
NSN 6645-00-988-3167
NSN 6105-01-623-1922
NSN 6620-01-495-7446
NSN 5920-01-444-4082
NSN 5998-00-445-5004
NSN 6240-01-360-6213
NSN 6150-01-578-8481