A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5910-01-415-1214
NSN 6145-00-343-5967
NSN 6135-01-604-8739
NSN 5985-01-213-1972
NSN 5935-00-001-4127
NSN 5990-01-429-6211
NSN 5960-00-378-1268
NSN 6135-01-617-9935
NSN 6620-01-232-8552
NSN 6105-00-141-5598
NSN 6130-00-226-2104
NSN 7035-01-628-3485