The Xit MB-D12 Pro Series Multi-Power Battery Grip allows the Nikon D800 & D800E to be powered by two EN-EL15 batteries ? one in the camera body and one in the MB-D12 ? effectively doubling your shooting capacity. The MB-D12 also provides a comfortable vertical grip with an additional shutter release and scroll wheel for easy access to the camera functions when shooting in the vertical orientation.
With the included AA battery holder, users can also power the camera with 8 AA batteries.