Lightweight portable transmitter/charger for iPod/iPhone 3G users on the go. Simply plug it into your car's cigarette lighter, make sure your car radio and Fm Transmitter have matching frequencies, and connect it directly to your data/charging port on your iPod to charge. Digital Wireless Radio Transmitter wirelessly connects your iPod/iPhone 3G to your car stereo and enjoy your digital music with full stereo sound at CD quality. Built-in USB port enables charging other mp3 players, cell phones, PDAs. Remote control allows you or your passengers to control iPod/iPhone 3G wirelessly. Adjustable arms open by a click of a button on the side. For iPhone 3G users: Upon plugging the fm transmitter into select device dock connection, the device will ask to go into airplane mode. Do not choose airplane mode. Make sure to keep the iPhone in 3G network for the best sound quality.