Tether Tools Relay Camera Coupler CRBLH-1. Relay Camera Couplers work in tandem with the Case Relay Camera Power System to keep your camera powered continually with an external 5V USB battery pack or wall power.
The Relay Coupler is simply an insert for your camera battery cavity that enables powering the camera via Case Relay Camera Power System.
The coupler does not contain a battery or hold a charge.
Coupler : Olympus Battery BLH-1 (CRBLH-1) Battery Grip Required
The battery door of the camera or battery grip must remain open. The camera will still operate correctly.