For easy Bluetooth retrofitting of vehicles with AUX-In, for wireless music transmission via Bluetooth 5.1 from mobile devices to car audio systems. Integrated analogue output (3.5 mm plug) to connect to the AUX-In in the car and then simply play music from the mobile device e.g. smartphone and enjoy the better sound from the car audio system. Bluetooth connection and hands-free function in one adapter thanks to integrated microphone. 2 multifunctional buttons for call acceptance or termination and for music control.