The X-One Biphase tennis string from Tecnifibre offers the highest level of control & power for professional athletes. This multifilament string is known for preserving playing qualities, as well as it features a wear indicator to establish when the string is due for a replacement. The string offers excellent tensile strength & longevity thanks to the Biphase pre-stretching process, & the PU 400 material grants substantially more elasticity when compared to similar strings. If integrity, playability & durability are what you seek, those are the pillars of the X-One Biphase range. Shipped as a 12.2m (40ft.) set.