The device transmits waves to the car radio, which plays sound from a microSD card or directly from the phone via Bluetooth. Additionally, it functions as a hands-free kit thanks to the built-in microphone. Technical specification: power supply: 12/24V cigarette lighter socket Bluetooth 4.2 Distance from microphone: 0.5-2m Bluetooth range: 10m microSD card slot dedicated buttons for phone calls File format: MP3 / WMA FM frequency: 87.5 – 108.0 MHz 2x charging USB socket (5V 1A and 5V 2.4A) attachment with 3M tape or magnet panel with a diameter of 6 cm length. drivers: ok. 110 cm Number of pieces. in the carton: 150