After researching several extended batteries for the iPhone 4, I chose this one because Scosche listed it as compatible on their website. While it does in fact charge the iPhone 4, it does not come close to matching Scoshe's claim's. On successive trials, it was only able to increase the charge of the iPhone's battery a little over 40%, not even close to the "complete" charge Scosche claims. Additionally, the design is lacking, requiring a separate charging cable utilizing a mini-usb connector, instead of the iPhone connector for charging, meaning one has to carry a second cable to charge it. The battery also utilizes a series of bright LEDs to provide status, which are distractingly bright. The Scosche logo is also illuminated, providing power to yet another LED. I would prefer it if those milliamps were put into serving the purpose of this device, charging my iPhone's battery, not advertising a company I will never purchase from again.