Maximal Power Battery with Case for iPhone 3G/3GS - Black More than 2 times of your Iphone 3g, 3gs battery Upto 12 hours in talk time or 7 hours for internet, and upto 380 hours of standby time Light Weight only 2.7 Ounces 1900mAH Rechargeable Lithium Polymer Battery Non-Slip, Stylish and Thin Grip