A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6220-00-891-5227
NSN 5996-01-544-3605
NSN 6620-01-615-2322
NSN 5965-01-518-8194
NSN 5905-00-533-7287
NSN 5960-01-023-2815
NSN 5910-01-226-6891
NSN 5855-01-641-8826
NSN 5990-00-915-4531
NSN 5975-01-399-8564
NSN 6685-00-469-7556
NSN 5935-01-360-6125