1、Applications: This tripod mount ring is specially designed for RF 100 to 400mm F5.6 to 8 IS USM lens, weighing approximately 122g, with an inner diameter of around 86mm. 2、Aluminum Alloy Material: Made of aviation grade aluminum alloy, CNC precise machined, the tripod mount ring is equipped with built in anti slip pad to protect your lens from scratches. 3、Effective Fixation and Balancing: Can be mounted on a tripod to securely fix and balance heavy telephoto lenses or to suspend them from the front of the camera, relieving the weight of the lens from the camera body. 4、Extensive Expansion: The bottom of the lens collar features a 70mm quick release plate with 1/4 inch, 3/8 inch screw holes and for Arca port, compatible with tripod ball heads, panoramic heads, and clamps. 5、Easy Installation: This camera lens tripod mount ring is easy to install with a large thumb knob that can be loosened or locked to effortlessly release and secure the lens.