The Canon BG-E11 Battery Grip is an optional power pack designed specifically for the Canon EOS 5D Mark III Digital SLR Camera. It holds up to two LP-E6 battery packs or six AA Batteries (with included battery magazine), offering double-length shooting time. This is very useful when using the camera's movie or Live View modes where you use more power. The Canon BG-E11 Battery Grip features a variety of operating controls such as shutter button, Main Dial, multi-controller, AF point selection button, AE lock/FE lock button, AF start button, and multi-function button, all of which can be independently turned on or off as you need. The BG-E11 is Ideal for easy vertical shooting.