Immersion Tin pcb board

4-Layer immersion Tin pcb board. the base Material is FR4 KB6160 (TG135). 4-layer PCB.Copper thickness is inner-layer 2oz and outer-layer 2oz finished.Board Thickness is 1.2mm and the Min.Hole Size is 0.2mm. Min.Line Width/Min.Line Spacing is 0.2mm/0.2mm. green solder-resist & with large white silkscreen. E-test: 100%.
Immersion Tin is a common surface treatment, relatively cheap.The advantage is that the surface is smooth and easy to do pcb assembly.