The canon bg e11 battery grip for eos 5d mark iii5ds and 5ds r is made from magnesium alloy and is designed for photographers who want to shoot for longer the ergonomically designed bg e11 grip doubles the battery life with two additional lp e6 batteries with the added flexibility of using aa batteries as an emergency back up for those who like to shoot vertically such as sports or portrait photographers duplicate af start focus point and ae lock controls in addition to a second multi con