Pittsburgh-based Allegheny Technologies Inc. has supplied its 425 Aerospace Titanium to companies building everything from ballistic armor to spacecraft. Now you can add golf clubs to the list. The unique alloy is used in the face of Titleist's TSi2 and TSi3 drivers. With a ductility 30 percent greater than the 6-4 titanium used in nearly every competitor, it provides added ball speed for extra distance across the face. The heads of the clubs are also more aerodynamic and were designed using feedback from PGA Tour pros. The TSi2 is built with a deep, low CG for forgiveness and added distance, while the TSi3 has a SureFit CG track that offers five CG positions to fine-tune ball flight. They're joined in the lineup by the matching TSi2 and TSi3 fairway metals, offering similar benefits to the drivers.