This Kupo 3/8"-16 Threaded Mounting Plate with Baby 5/8" Stud is an aluminum disc with a 5/8" stud on 1 side and a standard 3/8"-16 mounting screw on the other. It's ideal for attaching a tripod head or other accessory to a Kupo Convi Clamp or any other piece of grip equipment with a 5/8" receiver.