The Canon 5D Markii Battery Grip is an optional battery grip designed specifically for the Canon EOS 5D Mark II. It allows users to load a choice of one or two LP-E6 battery packs. With two packs, the already-impressive battery life is doubled, compared to using a single LP-E6 pack in-camera. This is especially useful when taking advantage of the cameras movie mode or Live View mode operating modes that use more power. In addition, with the included BGM-E6 Battery Magazine, you can alternatively also run the camera off six AA batteries.