Butterfly Sriver FX rubber has long been a mainstay with players around the world. Since its inception over 40 years ago, Sriver has proven itself at every level of competition. Perfect for the allround attacker, Sriver FX has a harder rubber top sheet, making it capable of good spin while still maintaining control. Also, the medium soft sponge lends itself to controlled attacks and blocks, yet it is easier to generate speed and spin when transitioning to offense. For allround players, developing attackers, and those seeking a good balanced rubber, you cant get any better than Butterfly Sriver FX! Surface: Inverted Speed: 10.0 Spin: 8.0 Density: 33 To get the most out of your rubber, it is recommended that you clean it after each use and store it properly. Using our Racket Care Kit, use one pump of the Spin Refresh on each side of inverted rubber, then use the Rubber Care Sponge to thoroughly clean it. Once it is dry, apply your protective sheets and then place it in your case. Ideally, store your paddle in a climate-controlled space and avoid extreme temperatures for extended periods of time.