Slim & slick, this cover cover gives you exactly the boost of battery you need to keep your iPhone going for longer enabling you to do more! Adds just a bit of bulk and a tiny amount of weight. Fits the phone quite snugly while keeping a nice smart look. The cable allows you to charge and sync your iPhone without having to remove the cover and the native iPhone battery is always charged first. A button at the back with a few LEDs lets you keep track of how much extra battery you've got left and also lets switch the batery pack on and off so that you can get that extra when you need it and allow you to manage your consumption (although I personally prefer having it on all the time). All the buttons and switches are kept easily accessible unlike some other iPhone covers. All in all I was very happy with my purchase it was exactly what I was looking for.