6-layer immersion gold E-paper main board pcb 1)Base material:FR-4 2)Surface Finishing: HAL ... :UL,ROHS,REACH,IS 6-layer immersion gold E-paper main board pcb1)Base material:FR-42)Surface Finish :HAL3)Certificate:UL ... ,ROHS,REACH,ISO9001,T/S169494)board thickness:1.6mm5)Min hole size:0.3 mm6)Min ...