Layers:2-24 Surface finish: Gold plating. Immersion Gold\Silver\NI\Tin.Gold finger \OSP and so on. Min board thickness: 1-2layers 0.2mm \4layers 0.4mm \6layers 0.8mm \8layers 1.2mm.... Min line widthing/spaceing: 0.1mm(4MILS)\ 0.1mm(4MILS)