(1)Immersion Gold (2)UL:E313409, ISO9001:2000,Rohs (3)FR-4 (4) ... Hole Size3milMax Finished Thickness8mmAspect Ratio≤12:1Max Layers36 LayersSurface FinishImmersion Gold, Immersion Silver, Immersion Tin, HASL, LF-HASL, OSP ... , Gold Finger, etcBase Material TypesFR-4, Metal Base(Aluminum base,Copper ...