... copper:35-55um Thicknes:1.6mm Surface Treatment:immersion Ag Sterling silver PCB Layer:8Min.Hole copper:25umSurface copper:35-55umThicknes:1 ... : HASL / HASL lead free, HAL, Chemical tin, Chemical Gold, Immersion Silver/Gold, OSP, Gold plating · Solder Mask Color: Green/Yellow/Black ... printed circuit board assembly as well as electronic encased products. Sterling silver PCB