ReFuel GoCharger 5200 mAh Power BankNow here's a fresh idea. Imagine a USB power bank that could recharge any of your portable electronics, that's very clever. Now imagine the same power bank but powered internally using two Hero4 batteries, that's brilliant! That means you can charge any other gizmo, but if need be, just open up the device and pull out the two Hero4 batteries (AHDBT 401) and insert them in your Hero4 camera (Silver or Black) and record as usual.