The device transmits waves to the car radio, which plays sound from a microSD card, flash drive, 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 5.0 Distance from microphone: 0.5-2m Bluetooth range: 10m microSD card slot voltmeter - battery charge meter 7 colors LED backlight (changeable via button) USB port for device charging with Quick Charge 3 standard.0 USB port for music playback from a flash drive / charging 5V 1A dedicated buttons for handling phone calls File format: MP3 / WMA / WAV / APE / FLAC FM frequency: 87.5 – 108.0 MHz Number of pieces. in the carton: 150