The Core SWX DV-GP4-USBC is a power extension cable that lets you power your GoPro HERO4 from a USB power source. It comes with a clear backdoor that attaches to the rear of the camera's Standard Housing and provides rain and splash resistance (but it's not submersible). The backdoor does not prevent visibility of the rear LCD of the HERO4 Silver Edition.
On the camera end, the cable locks into the bus connector on the back of the camera instead of into the camera's USB port, providing for a more reliable connection, highly beneficial in high impact applications. Another benefit of this power solution is that no heat is generated, since what's being used is simply a cable and not a battery, and this reduces the chance of overheating the camera. The cable is 10 ft long.
Although the HERO3 uses the same bus connector, this Battery Eliminator is only compatible with the HERO4.