iPhone 4,All iPod models,iPhone,iPhone 3G,iPhone 3GS or any device that ... mm headphone jack of any portable audio player 2. Play your music to any FM radio3. Backlit display is easy to read ... /step5. Memorizes the last frequency6. Supply power to FM Transmitter using included car charger 7. CE,FCC & RoHS approvel FM Transmitter for iPod,iPhone 4,iPhone 3GS & MP3 Player