It's working perfectly after 3 months. It does about 2-2 1/2 iphone 4s charges depending how low the iphone battery is. Charges anything that takes a 12v output. I.e. phones & laptops. You will need your own usb leads for each seperate device. Would recommend.
Great value for the money compared to anything else. Worked fine straight out of the box. Bear in mind it's tiny. 3.5cm high by 3.8cm wide. Fast delivery. Plastic casing and obviously not shock proof or droppable. We'll see how it stands the test of time.
All in all a great bit of kit and good value for money. It still works well after 4 months of use and I have the phone on me all day. It is robust, feels comfortable and extends the battery life for the iPhone 4S but it has an inherent weakness on the top clip part of the case. It became lose after two weeks and will not stay attached securely to the case. I have had to tape the top clip to the bottom case to keep it in place.