Callaway Big Bertha Fusion 3 wood 15 (NVS REGULAR) Golf Club 3w Callaway Big Bertha Fusion Variable Face Thickness (VFT), a patented Callaway Golf technology, maximizes the Moment of Inertia (MOI) of the club head for maximum speed and distance S2H2 and Tru-Bore technologies provide optimal weight distribution and improved feel and control at impact