Happy owner of an iPhone 4, my car is unfortunately not equipped with a USB port and listen to my playlists, I spent so far by the jack input available on my Peugeot and the output jack (headphone jack) iphone. Result, I could listen to my music but must recognize that the sound was not transcendental (a priori linked to sound filter iphone software). Then I came across an article about this small module Fiio L11 which is intended to circumvent the software filter / amp iphone, via the dock connector. He ordered there's three days and received today, I plug immediately on my precious, the jack connects to my car and there ... a miracle! a sound that has nothing to do! Powerful, light, I rediscover my favorite tracks and I feel we just settle a premium sound system in the car. In short, I am delighted with this purchase which has radically improved the sound quality when listening to the Iphone. I highly recommend!