Thanks! When you order your COBs, I'd recommend going with the Vero 29s instead of the Cree CXBs. This driver will only drive 3 Vero 29s while it will drive 4 CXBs, however, the Veros have a flat aluminum back that can be mounted directly to the heat sink (with a little thermoconductive grease) for 100% contact while the Crees need this flimsy mounting bracket and still won't have 100% contact for heat transfer to the heat sink. Whichever you choose, good luck with your build!