✓ WORKING WHILE CHARGING?The portable bluetooth car stereo receiver support up to 8.5-9 hours of use after full charged in about 2 hours. It can also be charged directly while playing music using a USB-C cable (included). If you encounter any problems during use, please contact us and we will help you at any time. ✓ SWIVEL JACK? The bluetooth car adapter aux input jack is flexible and you are able to move it so you can get it in a very good position in your car or other stereo devices. Designed with MFB and volume up/down button, it is very convenient to adjust the volume of music. ✓ STABLE CONNECTION?This Bluetooth 5.2 music receiver establishes an ultra secure connection between your phone and X4 Pro so you can enjoy skip-free music and calls no matter what road you takes. After starting the device button, automatically connects to the last connected device. ✓ ENJOY HANDS-FREE CALL?Our bluetooth headphone adapter supports hands-free calling with a built-in microphone and one button for answering, hanging up, rejecting, redialing calls. This device is your best companion on the road, ensure driving safety. ✓ SAVE YOUR MONEY?The smart Aux bluetooth adapter can upgrade any of your old car truck vehicle or home sound system into wireless via the 3.5mm jack instantly. No need for expensive modification of your stereo or other expensive bluetooth receivers.