Players with long fast strokes should love this Yonex Ply Tour Fire! It is a monofilament polyester string that has been manufactured using the Yonex Silicone Oil Infused Filament Technology. Yonex has made this string with its unique Silicone Oil Infused Filament (SIF) Technology. This helps players to generate heavier spin due to the reduction in friction as the strings snap back faster. The feel is firm but nicely dampened, with a surprisingly low level of shock on off-center hits. Suitable for harder-hitting advanced players who want to control and dominate play from all areas of the court.