The tripod ring allows you to mount and balance your heavy or while the lens is attached to the front of your camera. Fabric on the interior of the tripod ring provides protection from damage to the camera lens. By adding a tripod collar to your lens you can achieve better balancing on a tripod. In addition, rotating the camera will now be much easier and faster. Inner diameter of ring is approximately 67mm. Compatible with:Nikon AF-S NIKKOR 70-200mm f/4G ED VR lens Tripod Ring Specifications: METAL construction Ring diameter: 67mm