Phil Mickelson started using a prototype of the Callaway XR 16 Sub Zero driver during this year’s West Coast Swing. The company is now set to make the club – designed for golfers who swing fast and generate a lot of spin off the tee – available at retail.
The 440cc head has the lowest center of gravity Callaway has designed into a driver – the company says the CG is below the neutral axis. Most drivers have a CG above the neutral axis, a hypothetical line that extends perpendicularly from the center of the hitting area toward the back of the club.