COB MCPCB(known as Chip-on-Board Metal core pcb) is semi-conductor assembly technology, where micro-chip also known as die is electrically interconnected instead of using traditional assembly process or individual IC packaging on the final product board. COB MCPCB used in thermoelectric separation application products. 
For normal MCPCB, there's a dielectric layer between trace copper and metal core, and the thermal conductivity is limited by that dielectric layers, so value can only be 1~3 W/m.K. But using COB MCPCB, there's no such dielectric layer because chip (die) direct touch the metal core, so thermal conductivity value of COB MCPCB will be almost the same one of metal core material itself. The normal material of metal core is aluminum, so thermal conductivity of COB MCPCB is more than 200W/m.K.

Material: Mirrow Aluminum
Number of Layers: 1 layers
Thickness: 1.6mm
Color of Solder Mask: White
Finished Immersion: Mirror Silver