The professional is modelled on a natural gut string and consists of the ISOSPEED Power Ribbons in the core as well as in the coat. The jacket is welded to increase the lifespan, the power ribbons are freely movable in the core. The result is a very good ball acceleration with optimal arm protection. Product Features: Material: Sheath: Polypropylene, Welded Power Ribbons, Core: Polypropylene, Power Ribbons, Pre-tension: String core Power Ribbons, Pre-stretched. Tips for king: 10 to 15 % softer spread; designed for small to medium striking surface size and tight string image. Length: 200 m. Diameter: 1.20 mm.