The Olympus Power Battery Holder HLD-6 is a dust- and splash-proof battery holder / grip combination that has been designed especially for use with the Olympus E-M5. You can separate the unit into 2 parts: One fit for shooting in landscape orientation and the other better suited for portraiture.
The landscape unit features an integrated shutter button, plus a dial for locking the grip onto the bottom of the E-M5. The portrait unit has a molded grip to ensure sturdy shooting while your camera is being held in the vertical (portrait) orientation, as well as a built-in shutter button and 2 built-in function buttons that can be programmed independently of those on the E-M5 body. It also includes a DC-IN jack for continuous powered shooting, which requires the optional AC-3 Power Adapter (not included). There's also a compartment allowing for the storage of an optional additional BLN-1 lithium-ion battery.
When shooting with the E-M5 and 2 batteries, you may select which battery to use first. Then, once that one is drained, the camera will start using the second, providing uninterrupted shooting.