A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6650-01-261-5239
NSN 6110-01-432-0758
NSN 5965-01-602-5436
NSN 6240-00-852-0688
NSN 5965-00-089-2712
NSN 5998-01-060-4450
NSN 6105-01-469-7769
NSN 6645-00-819-5045
NSN 5985-00-924-2884
NSN 5920-01-483-7632
NSN 4140-01-263-9065
NSN 6150-01-226-7433