... immersion tin, plating goldBoard Panel Size: 400mm*610mmBoard Layer: 1L-4LBoard thickness: 0.1mm to 0.25mmFinished ... base material Polyimide (PI), polyester (PET), FR4 layerSingle-layer, double-layer, multi-layerCopper thickness12um, 18um, 35um, 70umWorking panel size400mm*610mmsurface ... (2mil)External treatmentrouting, punching, laser appearance 6 Layer FR4 and PI optical pickup head fpc board