DSTE Pro BG-E2N Vertical Battery Grip + 2x BP-511 Battery for Canon EOS 40D 20D 30D 50D SLR Digital Camera A firm, comfortable grip for vertical-position shooting with the Camera. Buttons and controls are conveniently placed and easy to reach for greater comfort. Holds two Li-ion batteries or six AA Battery for extended shooting Li-ion Battery Info: DC 8.4V (max); DC 7.2V (mean) 17.0Wh/2300mAh When using two batteries, the grip will automatically switch to the second battery if the first becomes depleted. Switching does not interrupt camera operation. Remaining power indicator