Delivering intense bite and control with new technology, Yonex Poly Tour Rev 16 tennis string is prime for adding spin to your game. Baseliners that have medium to fast swing speeds can take full advantage of the string's octagonal shape and intense bite on the ball. What makes this string stand out is the new SIF (Silicone oil Infused Filament) technology to improve spin and snapback. Combining SIF with the string shape creates a faster moving string with a firm feel to deliver great spin and control to your game.