On the ultra-simple and an effective permanent installation, the highlight of the Juice Pack for i4 is qu'l it is perfectly forget! You get used very quickly to her new iPhone slightly thicker and heavier, but with a virtually unchanged aesthetics, sound improved significantly and of course a doubled autonomy, perfect for movies. One small detail annoying trouble: when the iPhone entered by the slice to take it out of a pocket, sometimes the upper part of Mophie is unclipped. Overall an excellent product at a very reasonable price after all. This accessory could have come out of Apple cartons without blushing! HIGHLY ADVISABLE!