It seems all I can do is echo the already glowing comments on this driver. I traded in my r7 quad in favor of the Callaway GBBII 415 10* w/ YS-6 Stiff shaft (after purchasing and loving two Big Bertha metalwoods). The head size is perfect, as I simply cannot find any playability above 440cc. I'm told that the ERC Fusion will be coming out shortly in 415cc, as well as a Pro Series (like Mickelson's).