The Bluetooth 3.5mm Aux receiver can turn your old car audio/home audio/3. 5mm wired earphones/speakers into wireless. Compatible with most Bluetooth-enabled devices, such as smart phones, tablets, laptops, and computers. This Bluetooth AUX receiver can pair with Bluetooth devices and the built-in microphone can be used to answer hands-free calls. One key to answer, reject, end and redial the last number. Designed with MFB and volume up/down button, it is very convenient to adjust the volume of music.