All Tecnifibre multifilament strings are made in France and are unique in their construction, with a PU saturation throughout the thousands of filaments instead of just an outer coating as offered by other brands. The result is an untouchable elasticity factor offering maximum power and comfort. X-One Biphase packs all of Tecnifibre's know-how into one string to provide the player with ultimate power and touch. Featuring a 400% elasticity factor like 305, but with H2C fibres for better tension maintenance, Elastyl fibres for more power and a Biphase process to aid durability .