SaFPWR Milano Smart Battery Case for Apple iPhone 4 & 4S Rechargeable Portfolio Cover - Smooth Black Leather - Bulk Packaging Rechargeble patented smart battery inside a stylish, protective, leather case; made for iPhone 4 & iPhone 4S. Patented Energy Management Technology doubles your iPhone run time and extends your iPhone battery life Adds up to 11 hours of additional talk time and up to 9 hours of additional web browsing on 3G ( 15 hours Wi-Fi) to your iPhone battery 2,200 mAh lithium polymer SaFPWR smart battery, rechargeable for over 500 cycles BRAND NEW!!! Ships in ECO-Friendly Bulk Packaging