Save over $12 with this 4-pack of Luxilon ALU Power. This iconic string combines great durability with impressive power and incredible control. Used by several ATP Tour professionals, including Juan Martin Del Potro. The durable and control oriented response of Luxilon ALU-Power and other Luxilon co-polyester strings has revolutionized professional tennis. By far the most popular choice on the ATP Tour, Luxilon's co-polyester monofilament construction allows a player to take full cuts at the ball without any loss of control. Players with fast swing speeds also tend to find these strings very spin friendly.