It is nearly impossible to make a device so thin and light without sacrificing features or performance. Yet iPhone 5 achieves that goal. It is an accomplishment of engineering as much as one of design. Every detail and every material — particularly the sleek aluminum enclosure — has been meticulously considered and refined. And it is made with a level of precision you would expect from a finely crafted watch, not a smartphone. As a result, iPhone feels substantial in your hand and perfect in your pocket. It is impressive that iPhone 5 gives you long battery life so you can easily make it through your day. You get up to 8 hours of talk time, up to 8 hours of browsing over cellular networks, and up to 10 hours of video playback.2 But it is extraordinary that we fit such a powerful battery into such a thin and light design — all thanks to Apple scientists who created unique battery chemistry instead of settling for a large, off-the-shelf option.