CLOUDSFOTO Pro Nikon Metal Tripod Collar Mount Ring for Nikon Af-s 70-200mm F/4g Ed Vr Zoom Lens Rt-1 Replace The metal tripod mount ring mount on the tripod, it helps you fix and balance your Tele-lens which is heavy or long lens hanging off the front of camera. Metal Construction,Best used with a tripod for stability and ease of use Fotasy is a registered trademark Replaces Nikon Tripod Collar Mount Ring RT-1 Fits Nikon AF-S NIKKOR 70-200mm f/4G ED VR lens