... Green solder mask, Hasl lead-free 3. Impedance control board 1.FR4 material, board T1.6mm2.Green solder ... mask, Hasl lead free3. 4 Layer Impedance control board4.Fast delivery time,with competitive pricing5. Application ... for PCB BoardMaterial type: CEM-3,FR-4,FR-4-TG170/TG180,Halogen Free,Rogers,Arlon,Taconic,Isola ... OZCopper thickness in hole: >20um FR4 4 Layer Impedance Control PCB