A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6130-01-519-4036
NSN 5920-01-329-4571
NSN 5910-01-432-3390
NSN 5920-01-275-0743
NSN 6645-01-446-5419
NSN 5910-01-503-8366
NSN 6620-01-286-2204
NSN 7035-01-271-1643
NSN 6130-00-248-7244
NSN 2925-01-143-4229
NSN 5945-00-228-5838
NSN 5996-00-543-1566