The 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 positive locking strength and precise control. The cine industry also refers to it as a "lollipop". When you need to crank down on a large overhead frame to hold it in place, this is the grip head for the job. The KG400512 is designed to convert a junior stand with a combo head into an overhead stand.