Product function: used to equip with external m.o.s.t. optical fiber amplifier (audio gateway), when adding aftermarket audio head unit, this module guarantees factory amplifier, speaker and sound quality. Processor function: used to upgrade Mercedes-Benz/Porsche car audio head unit. Compatible with: for Mercedes-Benz head unit replacement interface Compatible with: Porsche head unit (PCM2, 2.5) replacement interface) Name:Optical Fiber Audio Decoding Box Working voltage:12V Applicable car series: For Benz ML/GL/R class 2005-2012 For Benz CLS/E/SLK Class 2009-2012 For Porsche Cayenne 2005-2011 For Porsche Cayman 997/911 2005-2011 For Porsche Boxster 718 2005 - 2011 Material: ABS colour: black 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.