A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6130-01-562-0431
NSN 5965-00-959-4910
NSN 2925-01-488-5140
NSN 5905-00-152-4080
NSN 6220-00-751-9709
NSN 6645-00-010-3054
NSN 5910-01-030-1410
NSN 5998-01-429-1076
NSN 5930-00-419-7820
NSN 6150-01-364-0331
NSN 6145-01-611-9505
NSN 6650-01-023-7002