This PROMASTER power grip is specially designed for the Canon EOS 5D Mark III DSLR cameras. It is equipped with an alternate shutter-release button, AE-L/AF-L button, and main dial for shooting in a vertical position. This power grip 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).