The Canon BG-E8 Battery Grip  for the EOS 550D/600D/650D/700D and EOS Digital Rebel T2i, T3i, T4i and T5i DSLR cameras holds up to (2) LP-E8 battery packs simultaneously to effectively double your shooting power, plus the grip includes a holder to use (6) AA batteries. 

In addition, the grip includes a vertical shutter release and a mode wheel to provide access to all of the camera functions and make shooting with the camera in a vertical position just as comfortable as shooting horizontally.