... Board 3.SGS,UL&ROHS Approval 4.Thermal consideration Immersion gold plated PCB prototype PCB process capability:1.Layer: 2-22 layer2 ... .Surface coating: Lead Free HAL, HAL, Flash Gold, Immersion Gold, Immersion Tin, Immersion Silver, OSP, Gold Finger Plating, Carbon Ink Printing, Peelable Blue ...