Kupo 4-1/2-Inch Grip Head with 1-1/8-Inch Stud and Receiver, KG400512The 4 1 2 Grip Head, KG400512 consists of a pair of rotating aluminum discs attached to a junior 1 1 8 (28mm) stud and receiver. The discs have two different sized V shaped jaws to accept any accessory with a 5 8 or 3 8 mounting stud or tubing. The V shaped jaws have teeth that grab whatever is mounted between the plates securely. The KG400512 uses a non slip aluminum friction disc that will maintain its durability over time that offers the user