1.[Main Function]: This is a car music bluetooth auxiliary adapter that can match the bluetooth module of your mobile phone or computer. It is used for wireless transmission of navigation, music, phone cells, ect. By using this adapter, you can use your car speakers to listen to sounds from mobile phones, computers and MP3 players. 2.[]: This wireless stereo receiver uses bluetooth 5.0 version of the main chip. By connecting the car audio through the wiring harness, the high-speed transmission will have no distortion, no interference and no loss. The sound quality can reach high-definition standards and is comparable to the original CD sound quality. 3.[Material]: The shell of the module music adapter is made of plastic material, which is durable and waterproof, and it's a good insulator. The plug is made of copper material, which has strong corrosion resistance, pressure bearing capacity and good electrical conductivity. The outside of the wire is wrapped with insulating material, which can effectively prevent leakage. 4.[]: Plug and play. Remove the CD player and insert the audio plug into the corresponding audio interface on the back of the player. The red wire is connected to the positive wire of the power plug, and the black wire is connected to the negative wire. Switch the car CD player to AUX mode and connect it to the phone via bluetooth.