A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5905-01-567-5947
NSN 5915-00-241-6493
NSN 6105-00-691-8493
NSN 5920-01-359-5925
NSN 5930-01-318-1553
NSN 5855-00-484-8638
NSN 5975-00-677-7803
NSN 4140-01-373-7044
NSN 6240-00-841-8734
NSN 6620-01-339-5524
NSN 5910-01-327-2720
NSN 5999-00-936-7789