This is bluetooth module is made specially for BMW vehicles. There is filter inside so when you switch between CD and AUX the sound volume will be same. Compatitible with : 2004 - 2010 BMW (E60): 5-Series: 525i, 525it, 528i, 528it, 540i, 540iT & M5 (Sedan and Touring) 2003 - 2010 BMW (E63) (E64): 6-Series: 630Ci, 630i, 645ci, 650i, M6 (Coupe and Cabriolet/Convertible) 2002 - 2008 BMW (E65) (E66): 735i, 735li, 740i, 740li, 745i, 745li, 750i, 750li, 760i, 760li (and diesel) *for M-ASK, ASK-CD and CCC BMW 1er Serie (E87, E88, E81, E82） Serie 3 (E90-E91-E92) This is bluetooth module is made specially for BMW vehicles. There is filter inside so when you switch between CD and AUX the sound volume will be same. Compatitible with : 2004 - 2010 BMW (E60): 5-Series: 525i, 525it, 528i, 528it, 540i, 540iT & M5 (Sedan and Touring) 2003 - 2010 BMW (E63) (E64): 6-Series: 630Ci, 630i, 645ci, 650i, M6 (Coupe and Cabriolet/Convertible) 2002 - 2008 BMW (E65) (E66): 735i, 735li, 740i, 740li, 745i, 745li, 750i, 750li, 760i, 760li (and diesel) *for M-ASK, ASK-CD and CCC BMW 1er Serie (E87, E88, E81, E82） Serie 3 (E90-E91-E92) Easy to install: 1.Insert the Black 12pin connector to the radio 2.Connect the red wire to 12V+, the black wire to 12V- 3.Pair your phone or pad with bluetooth module. 4.Choose Aux from your radio 5.You can use your phone to play music through car speakers. Cable length:25cm. High quality!!