Copper Base PCB, Metal PCB is the thermal conductivity dielectric material in the MCPCB. This acts as a thermal bridge between the IC components and the metal backing plate. Heat is conducted from the package through the metal core to an additional heat sink. On the FR4 board the heat remains stagnant if not transferred by a topical heatsink. LED PCB always be produced with Aluminum core, but sometimes steel core PCB and copper core PCB also be used. Copper Base PCB Metal PCB ENIG White 1 Layer, Copper base material. Finished board thickness is 1.6mm. White solder mask 1 Oz finished copper thickness. Surface Finish is ENIG 2u