This item has a 3.5mm female jack, you need to plug it into your Phone/i-Pod/MP3 player in one port, and plug another port into your BMW stereo to make sure it works.It will greatly show you the good sounds quality of your music because it had be plug into the aux port directly on the back of the head unit. Compatible with Model: BMW 5 Series (E39 with SA 661-650) BMW 5 Series (E60, E61) BMW 6 Series (E63, E64) BMW Z4 Series (E85 with SA 662) BMW X3 Series (E83 with SA 662) BMW X5 Series (E53 with SA 661-650)This aux cable is compatible with BMW X5 without navigationRadio Boost CD 53 / Business CD2003 - 2008 BMW (E85 / E86): Z4 (2.0, 2.5, 3.0 & Coupe and Convertible models) 2004 - 2010 BMW (E83): X3 (2.0, 2.5, 3.0 & xDrive models) SA 650 (Radio Business with CD drive) SA 661 (Radio Business with CD drive) SA 662 (Radio Business) How to use: 1.This cable simply connects to the back of the radio and provides an AUX input option on the radio or navigation display. 2.Once selected any audio source connected to this Aux input jack is played in stereo over the vehicle's speakers. 3.Open your CD changer, press MODE to see whether the AUX is on. 4.Then the CD MODE will show another mode AUX INPUT besides FM CD mode. 5.If AUX INPUT cannot show, then the cable cannot compatible, please contact with us to get the refund.Important Note: 1. Please compared the vehicle connector pictured above to the actual connector (12-pin socket casing). Please check, if your head unit has MODE button on it before you buy it. 2.There is a small arrow on one end of the connector. That needs to face up when you put this into the stereo. 3.Make sure you push the connector ALL the way in. It's a deep connector so make sure you push hard. 4.NOT compatible with older units, or without MODE button or cassette and Navigation Player