Suitable for Canon EF 70-300mm f/4-5.6L IS USM Ring inner diameter: 81.5mm, Ring width: 18mm, Ring thickness: 4.5-8mm Standard 1/4 in tripod screw thread The tripod mount ring mount on the tripod, it helps you fix and balance your tele lens whi is heavy or long lens hanging off the front of camera Fabric on the interior of the tripod ring provides protection from damage to the camera lens Specification: Ring width :Appro 17mm Made of metal The UNC Unified National Coarse Thread is 1/4'' Color: White Weight :164g Compatible with: Canon EF 70-300mm f/4-5.6L IS USM Canon EF 28-300 L IS Package Includes: 1x Tripod ring