technical parameters: Frequency point：87.5--- 108.5MhzFrequency scope：50-15000(HZ)Transmitter distance：more than 30meters how to use: 1 Plug the unit into cigarette lighter in your car. 2 Connect input connector in the unit to your portable device output jack and adjust the portable device output to proper level by volume control. 3 Turn the frequency of FM receiver in your car to the same frequency labeled on the unit and you can enjoy fantastic music in your portable device now