Product function: used to equip with external s.. 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 -/ car audio head unit. Compatible with: for - head unit replacement interface Compatible with: 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 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.