... Impedance Controlled, Vias Plugged with Solder Mask, RoHS Compliance. 12-Layer PCB,Taconic Material,2.0mm Thickness,Immersion Tin,Impedance Controlled ... +/- 2mil (0.05mm) Outline Tolerance +/- 4mil (0.1mm)S/M Pitch3mil (0.075mm)Aspect ratio12:1Finished Copper Weight10 ozImpedance Control ... , Carbon PrintingMaterialFR4, ROGERS, Taconic, ARLON, BT, Ceramic, Aluminum 12-Layer PCB with Taconic Material