The Tecnifibre X-One Biphase Orange Color 18 Gauge Squash String is a multifilament string, the fibers are immersed in polyurethane to provide ultimate shock absorption and optimum comfort. The X-One Biphase string uses High Heat Capacity (H2C) fibers, which allows the use of a new chemical treatment process called Trimerization. Trimerization increases the compatibility between chemical molecule links through extreme variations in temperature to result in ultimate efficiency and exceptional feel. This new patented process, extends string life by 20% and offers increased spin.