HIGH CLAMPING FORCE OF THE BACKPACK STRAP MOUNT: The anti-skid gear design inside the backpack strap clamp mount and the powerful spring device make the backpack phone holder have a strong clamping force. The backpack strap clip will clamp the backpack tightly and not loosen to ensure the safety of the mobile phone | The backpack clip for phone that can be rotated 360 degrees and the metal mobile phone clip that can be rotated up and down allow you to adjust the shooting angle at will to capture every wonderful moment | This backpack strap clamp for phone is suitable for most knapsack on the market. And the backpack clamp mount’s installation is simple and convenient, and the backpack clip mount is very suitable for going out to shoot video | The range of phone holder clip mount can be adjusted by rotating the screw on the side. The metal phone clamp can be applied to mobile phones with a width of 2.6 inches-3.2 inches (65mm-82mm）. The backpack clip is suitable for most smart phone sizes on the market, such as iPhone, Huawei, Samsung, and more | The phone holder setup is made of aluminum, the surface is sandblasted, and through anti-corrosion and oxidation treatment, which greatly improves the anti-corrosion performance. And there is a 1/4 standard threaded hole interface on the side