The Black Knight Ion X Force Yellow squash racket is the first model with the Power Surge bars that sandwich the throat & shaft, which results in X-tra stiffness, X -tra vibration dampening qualities, & X-tra power. The yellow Ion X Force squash racket weighs 145g, which makes it slightly heavier than the black version that weighs 140g, but both of them are very X-treme. This yellow squash racket is especially recommended for advanced or professional players. The head size of the racket is 475 sq.cm. It features a head light balance, 95 stiff rigidity, a 14x 16 string pattern, 25-29 lbs string tension & is strung with Super Nick XL Micro string.