A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5855-01-068-3683
NSN 5910-01-032-6209
NSN 5905-01-596-1688
NSN 5895-01-003-8464
NSN 6135-01-550-8998
NSN 6240-00-715-1046
NSN 5975-01-650-4467
NSN 5905-00-156-2982
NSN 6135-01-177-3552
NSN 5945-00-005-0325
NSN 6620-01-535-4358
NSN 5930-01-338-1615