Initially designed for the twilight of his playing career, the RF 01 Pro underwent exhaustive testing and tweaking by Federer, bearing the mark of insights gleaned over one of the most remarkable careers in tennis history. Compared to his RF97 Autograph, the RF 01 Pro has a slightly more forgiving head size, along with a lighter weight and thicker, more aerodynamic beam construction. The upshot is a more explosive weapon, one that is better suited to the speed, spin, and pop of the modern game. This racquet's design is appropriately named SABR, a moniker that epitomizes Federer's attacking style. It includes a powerful carbon fiber layup with Braid FORTYFIVE technology to enhance both dwell time and pocketing while helping the racquet bend in ways that complement the vertical mechanics of the modern game (think spin). It also features foam throughout the racquet to deliver a more solid feel, coupled with a reinforced shaft and yoke for more torsional stability (think less racquet flopping on volleys). Ultimately, the RF 01 Pro is not only a great snapshot of Federer s evolution; it's also hard to put down.