1、Applicable Lens: Lens collar tripod mount ring is suitable for Sigma 100‑400mm f5‑6.3 DG OS HSM Contemporary Lens (for EF Mount, for Nikon F Mount). 2、Quick Mount Plate: At the bottom of the lens ring is a 100mm quick mount plate with built in for Arca ports, 1/4 inch and 3/8 inch screw holes, compatible with tripod ball heads, panoramic ball heads, and clamps. 3、Lens Mount and Safety Stop Screws: The lens mount is installed on a tripod, which can help you fix 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、Aluminum Alloy Material: The lens collar tripod mount ring is made of aluminum alloy material, CNC precise machining, manual polishing, surface anodizing treatment, and strong durability. 5、Hollow Design And Strap Hole: The lens collar tripod mount ring adopts a hollow design for light weight, with a built in strap hole for easy carrying.