Allows you to connect an external audio source. It is possible from your smartphone to your car stereo to stream. Pair your phone with our bluetooth module, and choose Aux from your radio. Easy installation, Plug & Play. Easy via Bluetooth without complicated code connections. Type:3G Bluetooth 5.0, 4 times speed. Function via Bluetooth-enabled devices. No functional limitations of the car radio. Compatibility:For A3 A4 B8 B6 A6 C6 B7 C6 C5 C7 Q5 A5 A7 R7 S5 A6L A8L A4L For / for vehicles which has 3G system and please make sure it can swich to aux mode in green menu (swich "media" and swich "aux") Installation: 1. Black power cable connected to 3Gsystem. Make sure that is your aux in enabled in green menu (swich "media" and swich"aux") 2. Plug into the CD player Jack (please confirm corresponding socket), mobile phone is connected with the Bluetooth module, aux audio source selection, you can play mobile phone music. Notice: 1. Please confirm that your car with a -for Music Interface, it is generally in the armrest box or storage box, without this Interface will not be to use this product. 2. We don't confirm 100% to compatible above car model years .please make sure that connector can fit for your car Before you order it. Colour:Black Material:Plastic Package Contents: 1 * Adapter Cable Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.