A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5975-01-426-8968
NSN 6610-01-645-7515
NSN 6645-01-254-0489
NSN 2925-01-055-9705
NSN 6610-00-729-6479
NSN 5975-00-283-2997
NSN 6220-01-158-6556
NSN 5920-01-218-6191
NSN 5915-01-486-2527
NSN 6610-00-161-0680
NSN 6145-01-041-3057
NSN 6145-00-180-5805