A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6130-00-132-0483
NSN 6685-01-423-1064
NSN 6145-01-522-6870
NSN 5990-01-413-2405
NSN 6240-01-654-7974
NSN 6650-01-485-3444
NSN 6150-01-532-4461
NSN 5999-00-222-6226
NSN 6240-01-633-9357
NSN 6685-00-772-9615
NSN 6645-01-117-6156
NSN 5915-00-698-3563