Head You Tek IG Radical Pro Unstrung Tennis Racquet It is a futuristic material with abnormal behavior characteristics. More specifically, D3O belongs to a subcategory of "dilatant foams," which dramatically change their behavior under dynamic loading or impact. The new HEAD Innegra is used in this racquet's structure to integrate into the racquet for shock absorption and improved stability. As a result, vibrations are reduced by up to 17% on ball impact for unique control and precision. The beam of the racquet is 21.5mm, with a 98" head size. Integrated in the lay-up and positioned in the shaft area of the racquet. This frame uses D3O, which belongs to the smart materials category. The racquet weighs 10.9 oz and is 1" HL in balance. This model comes unstrung. The string pattern is 16/19 and the racquet is standard in length, 27".