The lightweight and extra thin Mi - Li Power Skin slides inconspicuously onto the back of your i - Phone 3G/3GS, adding just a few millimeters of thickness and up to eight hours of additional talk time. It prioritizes consumption, pulling power itself first, maximizing your i - Phone"s internal battery. The Power Skin allows access to the camera and headphone jack while weighing only 2.8 ounces. Fits i - Phone 3G/3GS, not included. - Ah lithium polymer battery Battery level indicator.