WRZ997112 - Available in 17 gauge / 130 / 1.3 mm 4G features maximum tension and a cushioned feel on impact, lending itself to excellent playability and adaptability to the modern game defined by power and spin. Boasting the elements of a control string minus the tension loss and discomfort of early polyester strings, 4G sets the standard for players craving precision. Used by many tour players, including the Williams sisters and Grigor Dimitrov. Wilson Luxilon 4G Tennis String 17 gauge Set | Christy Sports