The Tripod Twist Clamp Kit is a Replacement kit. It was designed to work with an Xit 404 Tripod Leg. If you have previously purchased an Xit 404 Ball Adaptor type Tripod Leg, you can remove the ball adaptor and upgrade with the Twist Clamp Kit. All parts are made from passivated Stainless Steel or hard anodized Aluminum for long life. The clamp mounts into a 1/4-20 threaded hole.