Description About this item Fix and balance your lens It helps you fix and balance your lens which is heavy or long hanging off the front of camera. Suitable for series Suitable for EF 70-200mm f/4L USM, for EF 70-200mm f/4L IS USM, for EF 300mm f/4L USM, for EF 400mm f/5.6L USM. High Quality Material Aluminum alloy construction, anti- and lightweight, to use. Easy to install Easy to install with a fixing screw stud and convenient to use.