The Battery Grip BG-E7 is an optional battery grip designed specifically for the Canon EOS 7D.Holds up to two LP-E6 battery packs to double shooting time or six AA Batteries (for emergency use)Following functions are available in the vertical shooting position- Shutter-Release， Main Dial， AF Point Selection， AF/FE Lock， Index，and moreThe vertical shutter release makes shooting with the camera in a vertical position just as comfortable as shooting horizontally.