KUPO KCP-600 Super Viser Clamp 4"(1) Anti Twist A clever groove notched into the back of the clamp keeps the jaws aligned with one another as they open and close. (2) Rubber Padded Jaws Mechanical interlocking design instead of glue between the rubber pad and the aluminum die casting jaws makes the rubber pad firmly attached to allowing secure mounting vertically or horizontally. (3) 16mm(5 8) Baby Pin The threaded shaft terminates in a 5 8 pin for mounting lights or grip