zTcase™ Window Flip Battery Charging Case Cover for Samsung Galaxy S4 Slim High Quality S4 GT-I9505 (Black)
Battery level, press on/off switch once to check how many juice left, see below indication.1 LED ≤ 25%         2 LED ≤ 50%3 LED ≤ 75%              4 LED >100% Charge/sync: Charging/sync, simple plug in the USB turn micro USB to the micro USB female dock, connect the USB to a powered USB equipment or computer.Before installing and using the product, please read the instructions thoroughly, and retain them for future reference.