This CAMVATE Adapter Set includes one 1/4"-20 female to 3/8"-16 male converter and one 3/8"-16 female to 1/4"-20 male converter. Both are made of brass with nickel plating and are knurled so they can be handled without any tools. One can be used to convert a 1/4"-20 screw to a 3/8"-16 screw, or vice versa, a 3/8"-16 female thread to 1/4"-20 female. The other converts a 3/8"-16 male to 1/4"-20 male, or 1/4"-20 female to 3/8"-16 female. They can be used for camera plates and various other accessories. A washer is included with each one for the male end to protect your gear.