Griffin iTrip Auto FM Transmitter + Charger with SmartScan and App Support for Apple iPod and iPhone, Black Works as inline remote to control play/pause, forward/backward User-programmable presets for often-used settings SmartScan one-button setup finds the best open frequency for you; all you have to do is tune your radio SmartSound adjusts signal levels to maintain highest sound quality Software app controller is a free download for iPhone and iPod touch