A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5975-00-242-6707
NSN 5925-01-353-5838
NSN 5965-01-352-1951
NSN 5990-00-351-5479
NSN 4140-01-630-7665
NSN 5999-00-850-7607
NSN 5905-01-310-6824
NSN 5999-01-592-2637
NSN 6620-01-575-6498
NSN 5915-00-318-1356
NSN 5935-01-048-9520
NSN 5975-01-079-4595