Features: The Bluetooth-compatible module is made for RD4 radio Just plug the 12pin connector into the socket back of your radio You can just Insert this item to the back radio then Connect the red wire to 12V+, the black wire to 12V-. Match your phone or pad to Bluetooth-compatible module.and Choose Aux from your radio, then you can use your phone to for play music through car speakers. You can hear music from your phone/pad/mp3(They should have blueooth function). Specifications: Color:Black Bluetooth-compatible Version: 5.0 Port: 12Pin Microphone length: 150cm Quantity: 1Pc Note: 1.Transition: 1cm=10mm=0.39inch 2.Please allow 0-3cm error due to manual measurement. pls make sure you do not mind before you bid. 3.Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you! Package includes: (Without retail package) 1 x Bluetooth-compatible Adapter