A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5945-00-840-5418
NSN 6130-01-447-2370
NSN 5920-01-247-7424
NSN 6110-01-542-9860
NSN 6110-01-547-5315
NSN 5990-01-553-6859
NSN 5945-00-136-8399
NSN 5920-00-122-5278
NSN 5855-00-185-1560
NSN 6645-00-634-9317
NSN 5925-01-322-3882
NSN 6145-01-352-6913