... Copper: 1 OZ / 35um; 3) Solder Mask: Blue; 4) Finishing: HASL Double-sided Prototype Board 1.6mm Blue color PCB ... ,Multi-Layer PCBMaterial Type94VO,FR-4,CEM-1,CEM-3,Aluminum PCBLayer Count1 to 8 LayersMax ... Lead-free HASLSolder MaskSolder Mask ColorRed, Green(Matte-Green), Blue,Black(Matte-Black), White, YellowSolder Mask Thickness10 ~ 25um ... Assurance Double-sided Prototype Board 1.6mm Blue color PCB