The X-ONE BIPHASE string is the best performing string in this range on the 3 criteria of playability, durability and integrity. The special feature of this range is the wear indicator, which allows the player to change the string before it breaks completely. This indicator is manifested by the significant fraying of the string at the point of impact of the ball. These strings are renowned and appreciated for their power, their comfort and their strong capacity to preserve their qualities over time.