The Wireless Radio Transmitter wirelessly transmits music from your iPhone 3G and iPhone 3GS or MP3 player to your car stereo. . The tuner locks digitally into the clearest available radio station. . Choice of channels (from 87.5 to 107.9 mhz with an increment of 0.1 mhz) allows you to choose the clearest available channel for best reproduction of music in your car radio. . The cradle adjusts to almost any position. Keeps your iPhone 3G and iPhone 3GS or MP3 player or PDA just where you need it to select the next play list and keep your tunes coming. . Convenient to use while listening to your favorite musics off your iPhone or MP3 player while resting on this holder that also functions as power charger through the car's cigarette lighter adapter.