mophie juice pack for Samsung Galaxy S4 seamlessly integrates power and protection to create the ultimate case solution for Galaxy S4. The 2300mAh battery will provide up to 80% extra power with the flip of a switch while the protective hard-shell case keeps your phone safe from daily wear and tear. Its slim design makes it easy for the juice pack to become your everyday case while still providing complete protection from your busy lifestyle. A smooth finish and pass-through buttons flawlessly blend the design of the case with your Galaxy S4. To make sure you always head out with two fully charged batteries, charge your S4 and juice pack simultaneously with the included micro-USB cable. Four LED lights on the back let you keep tabs on how much power is left in the juice pack battery, and, when charging, will keep you updated on its status.