1、COMPATIBLE MODEL: This lens collar is compatible with for Sigma 100‑400mm F5‑6.3 DG DN OS E Mount, for Sigma 105mm F1.4 DG HSM Art (EF FX FE L mount). 2、3 PORTS: The bottom of the lens ring is a 100mm quick mount board, built in for Arca port, 1/4in and 3/8in screw holes, compatible with tripod ball heads, panoramic stabilizer and fixtures. 3、MAIN FUNCTION: The lens tripod mount ring could help to secure and balance your lens. There are two safety stop screws on both sides of the bottom to prevent the device from accidentally falling off. 4、PRECISELY MADE: The lens tripod ring is made of aluminum alloy material and has undergone CNC precise machining, manual polishing, and surface anodizing treatment, ensuring strong durability. 5、LIGHT AND PORTABLE: The lens tripod mount collar ring adopts a hollow out design, which is light weight, with built in strap hole, easy to carry.