Use Instruction（Compatible with Mercedes-Benz car Only）: put the plug into the MMI port (Ｖery Important: please confirm your car have MMI Interface like picture show, it is a rectangular socket hole, not is a ipod pin plug or HIM port) then activate the AUX mode in the MMI system of your vehicle and pair it with your Android, iPhone, iPad or iPod touch via Bluetooth to play music (Note: MMI socket usually in the glove box) | Blue LED Light Up: bluetooth mode（USB port charging function off）, you can only change songs from the smartphone, can not control over music from the iDrive system , the playlist will not be displayed on the car screen | Red LED Light Up: USB mode（Bluetooth transmission function off）, you can charge your device, or use the U Disk to listen music (Note: U Disk must is FAT32 formt, suggest under 32G. there are few MMI system don't support U Disk function, if not fit, please contact with us to solve the issues) | Vehicle compatibility: Compatible with Mercedes-Benz A-Class W169 C169;B-Class W246 W245;C-Class W204 S204 C204;E-Class A207 S212 V212 W212 W211;S-Class C207;M-Class W166;G-Class G463;CLS- Class C218 C219;GLK-Class X204;SL-Class R230;SLK-Class R171 C639 NCV2 Vito.( Note: The detail compatibility of Month/Year please check:Product description; Not fit the model of C300/ E320/ E350 with iPod iPhone 30 Pin plug connecter and HIM interface) | Feature: bluetooth kit have auto connect recorded and 2 smartphones suported at same time.(this bluetooth adapter Sound stable and the Transmission quality will better than other FM channel bluetooth transmission product)