The new Pro|SL Carbon midsole utilizes two densities of foam plus carbon fiber to deliver optimal comfort, control, and Tour-caliber stability. A firmer foam around the perimeter offers stability and control, and an ultra-soft foam underfoot delivers plush cushioning. An integrated, precision engineered carbon fiber inlay provides both off the charts stability and advanced energy return. It’s engineered to limit torsional movement during your swing, and also flex with your foot as you walk to provide spring-like energy return and reduce fatigue with every step you take.