Well, the new Canon 5D Mark III is just different enough they needed to offer another battery grip. This wasn't the case for the Canon T2i and Canon T3i as they share the same Battery Grip. It's not required to have one, but I do like using it especially for Photography in portrait mode. The new BG-E11 battery grip for the 5DM3 still uses the same LP-E6 batteries, but the new unit will run you about $350 bucks. Thanks again Canon..