Active Speaker Wire Harness for Audio System Modification Kit1、Applicable Model: The audio activation wire harness is a replacement for 3 2021, please check the model and year of manufacturing before ordering. 2、Activate Speakers: The original car can only use 8 speakers. With this wire harness, you can activate the 4 inactive speakers on (only 4 in post March 2020 build) cars. Give you more wonderful music enjoyment. 3、High Performance: Designed with stable data transmission and lossless sound quality cable to give you a better listening experience, pleasure of being surrounded by music. 4、Fine Workmanship: The upgraded wiring harness does not require additional processing, the wire is thicker, the resistance is smaller, the sound effect is improved several times, and it is safer. 5、Non Destructive Installation: It is designed according to the original car interface, and can be inserted directly into the interface. Installation is simple and without any damage.