Very Important. Read before purchasing Mr12volt bluetooth is installed on the OEM radio via Fiber Optic (M.O.S.T). It delivers CD sound quality without any inteference. It provides bluetooth Handsfree & Music Streaming to your original radio. For Audio 20, It must posses a external CD changer In some cases, it is necessary to code phone features through computer so that Mr12volt P600 can work in handsfree mode properly, otherwise handsfree will work in CD mode. Model compatible: NTG 1 2, Audio 20 APS 50 Comand W211, W203, W220, R230, R171, C216, W209, W219, W164, X164, W169, W245, W463, W251, W639, C199 Features: Bluetooth Hands-free calling directly from the car stereo (microphone included) Bluetooth Audio streaming, Sound of music, navigation, podcasts etc. through the car speakers USB/SD music Playback, Aux-In Easy to use interface with menu browsing and music information on your car display Phone charging via USB cable (300mAh) Software upgradable Package contents: Black Box Module Fiber Optical harness Fiber optical bypass connector Power cable Microphone 3.5mm AUX in cable User Manual Supported USB devices: USB: Flash Memory and Hard Disk Drive (USB ver. 1.1 and higher) File System: FAT16 or FAT32 Storage capacity: up to 64GB music content