The only thing that makes contact with the ball is the string in the racquet. So you better make sure you choose the best. The new HEAD HAWK Tour string has been developed together with HEAD's top pro players. Thanks to innovative HEAD CRYSTAL CORE Technology it combines extraordinary energy efficiency for explosive power with optimized control and touch in every shot. Get ready to release the pro in you! The unique string manufacturing process which utilizes a complex, multistep heat treatment allows HEAD to control the molecular crystal structure within the string, engineering different material properties in the core and outer region of the string. This process sets Head Hawk apart from conventional polyester strings. Highly oriented molecules on the outside of the string generate stiffness and energy efficiency releasing more power and explosiveness. A more crystalline inner core adds dampening and touch to the string's performance. By creating unique variations in the molecular structure within the cross-section, it creates the highest possible energy efficiency for explosive power with optimized control and touch in every shot.