The HLD-4 Power Battery for the E3 Digital Camera holds two BLM-1 1500mAh rechargeable lithium-ion batteries. This unit not only holds the extra battery for more juice when shooting but provides an added gripping surface to the camera. For those with large hands, this is a huge benefit.
Why run the risk of running out of power during a crucial shoot? The HLD-4 Battery Holder should be considered an integral part of your Olympus E3 gear.