Product function: used with most external optical fiber amplifiers (audio gateways). When adding aftermarket audio head units, this module can the for original amplifier, speakers and sound quality. Processor function: used to upgrade for /for car audio head units. Compatible: used for head unit replacement interface Compatible: for head unit (PCM2, 2.5) replacement interface Name:Optical fiber audio decoding box Working voltage:12V Applicable car series: For ML//R class 2005-2012 For /E/ class 2009-2012 For 2005-2011 For 997/911 2005-2011 For 718 2005-2011 Colour:Black Material:Plastic Package Contents: 1 x Fiber Decoder Box 1 x Cable Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.