Battery Poign&eacute;e Grip Bg-e2 Bg-e2n for Canon EOS 20d 30d 40d 50d Digital Camera Battery grip with a shutter release button, and shutter function with AF Thumbwheel, aperture / exposure compensation button, AF point selection / Magnify button, exposure lock / flash exposure lock / index/ reduce button Load Six AA size batteries into battery magazine and insert the battery magazine into battery grip and screwed tightly for power life Load one or two BP-511 lithium battery into battery magazine and insert the battery magazine into battery grip and screwed tightly for power life Compatible with: Canon EOS 20D 30D 40D 50D