The X-Grip is one of the best-selling phone mounts on the market, providing a secure hold in nearly any environment. In demanding and open cockpit applications where excessive wind and g-force could cause movement of your phone within the holder, you can ensure added peace of mind with the X-Grip tether. It's also great if you just want a little added stability and vibration control when capturing video while your phone is mounted. The tether is made of high-strength elastomeric material and fits around the large X-Grip holder for easy attachment to your phone.