1.pcb layout 2.4layers with immersion gold 3.1.6mm thickness pcb layout 4.UL ... PCB specification DescriptionDetails SpecificationBase MaterialFR-4,Aluminium-backed board,Halogen-free,Lead-free compatible,High Tg,High CTI,CEM-1,CEM-3 ... ,OSP(lead freecompatible),Carbon ink,Peelable S/M,HASL(lead free),Immersion silver/tin,Gold finger plating,ENIG+gold finger plating ...