A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6130-01-497-7555
NSN 5915-01-559-8039
NSN 6110-01-412-8549
NSN 5910-01-501-6192
NSN 6220-01-216-0678
NSN 5910-01-556-4278
NSN 6650-00-842-5463
NSN 5990-00-331-4459
NSN 5998-01-054-2851
NSN 5835-01-471-5848
NSN 6620-01-411-5750
NSN 6135-01-294-2131