... PI material 2. 6L 1oz copper, Board Thickness1.6 mm 3. Competitive price with good quality ... 1. FR4+PI material2. 6L 1oz copper, Board ... Polyimide (PI), polyester (PET), FR4 layerSingle-layer, double-layer, multi-layerCopper thickness12um, 18um, 35um, 70umWorking ... treatmentrouting, punching, laser appearance 6 Layer FR4 and PI optical pickup head fpc board