1, KB base material 2,HASL, 35um,2-layers 3.Free sample 4.Best price and high quality Grandwork is professional and ... laminate, Metal core AluminumSurface Finish:Hot air Lev p lead free HASL, immersion gold/silver/tin, plating gold, OSPBoard Thickness:Inner ... forward to your inquiry! FR4 1.6MM Double side PCB(Free sample)