This adapter allows you to connect your mobile phone to the stereo system of older cars via a Bluetooth receiver. This allows you not only to play your favorite music or podcasts while driving but also allows you to answer calls as you would with a hands-free set. The adapter also includes a USB plug, allowing you to play MP3 files directly from a flash drive. The rotary button and screen integrate all functions of the product and allow for elegant and intuitive operation. This design allows the driver to answer the phone or switch songs safely and quickly without looking for the buttons.