Tennis followers know that Roger Federer has been seen playing with a mystery racket this year — and now we know why. The Wilson Pro Staff RF97 Autograph Tennis Racket is the 17-time Grand Slam champ's new signature tool, developed over three years in a close collaboration between Federer and Wilson. Features include a 97-inch head that provides outstanding feel, a 26-percent wider racket beam for more power, a 10 percent larger sweet spot, and a matte black finish. Still not sold? Well, consider this: the RF97 will be Wilson's first Autograph racket in 30 years, and the last one, the Jack Kramer, was the best-selling racket in history.