The Tecnifibre X-One Biphase 1.18 tennis string is ideal for players looking for maximum power, feel & comfort. This arm-friendly string provides good tension maintenance & a gut-like feel. The string utilises High Heat Capacity (H2C) fibres that provide superior feel & power, & the new Biphase process that increases strings durability by 20%. In addition, the string is covered with Polyurethane that reduces shock & improves comfort. The Tecnifibre X-One Biphase string has a 1.18mm gauge & is available in a 12.2m (40ft.) set.