1. the car kits can be used both of MP3 and mobile phone when you driving in the car.
2. it designed in mini car baby and made in good quality.
3. you can adjust frequency of car radio to FM88.9 and then you can hear the MP3 music in a nice sound from loudspeaker.
4. it used 2023 lithium battery. In the car kit package we attached two free batteries.