Genesis Black Magic Tennis Racket String, Black, 40-Feet/17-Gauge Black Magic leads the pack among co-polyester strings on the market today Offering a superb balance of power and control, Black Magic is bound to raise your game to a new level; This string excels when it comes to feel Most polyester strings today have one major flaw: they have no feel, Black Magic is the answer Softer than most co-polys, this is a great string for players that are looking for a comfortable poly offering a serious punch This thinner gauge provides added power and playability