... ,ISOLA(FR408,370HR),TEFLON,POLYIMIDE,ROGERS(RO4003,RO4350,RO4450),Aluminum plate (Single,Double-sided)FR4 Thickness1.6mmHigh TG FR4 (170 deg ... .1mm(0.004”)Semi-holeYSurface FinishHASL,HASL pb free,immersion gold,immersion silver,immersion tin,O.S.P (Entek),S/G ... and then set out to surpass them. 2 Layer Immersion Gold PCB With Gold Finger