A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6320-00-593-0379
NSN 5920-00-452-3889
NSN 5895-00-505-7453
NSN 5910-01-132-1399
NSN 6650-01-234-4378
NSN 5835-00-523-0736
NSN 6220-01-214-9463
NSN 5915-01-613-1294
NSN 5895-01-226-2762
NSN 7035-00-096-9986
NSN 6220-01-587-6452
NSN 6130-01-475-6051