A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6320-01-491-0327
NSN 5996-00-231-9322
NSN 6105-01-107-5991
NSN 6620-01-463-1373
NSN 5915-00-383-1471
NSN 5945-01-513-9686
NSN 5930-00-223-5224
NSN 6685-00-982-1960
NSN 5920-00-943-9763
NSN 6320-01-335-8336
NSN 6320-01-029-2196
NSN 5915-01-587-9009