Promaster Vertical Control Power Grip for EOS 5D Mark II equipped with an alternate shutter-release button, AE-L/AF-L button, multi selector, as well as main and sub-command dials for shooting in a vertical position. can hold two LP-E6 rechargeable Li-ion batteries to extend your shooting time or can conveniently use six AA batteries (alkaline, Ni-MH or lithium).