Prong, the company behind the iPhone case with a built-in plug for easy charging, today announced an expansion to its product line up, debuting the Prong PWR case. Like its existing PocketPlug combo cases, the PWR case includes an integrated plug for charging the iPhone, but it also comes equipped with a 1500 mAh detachable backup battery that can be used to charge the iPhone when it is away from a power source. The backup battery itself can also be detached and recharged via its built-in plug. The Prong PWR Case includes a detachable backup battery and integrated plugs for charging in any outlet, along with a Micro USB port and cable. The backup battery is easily detachable and can be recharged without any additional accessories while the smartphone remains with the user, sa