... certificate:UL,ROHS,REACH,SGS OEM,ODM HASL four layer pcb board CategoryItemHigh-volume processing capacitySample and small batch processingTechnology ... Immersion Gold, chemical Shen tin, electroless nickel deposit Lead-free HASL, Electroless silver, osp , Thick gold platingPlates ... size600mmX1200mm1200mm-2000mmImpedance Impedance Tolerance±10%±5% HASL four layer pcb board ,4 layer pcb board