Gamma Live Wire Professional 18G Tennis String, Natural Features Live Wire Multifilament Technology. Features an advanced string construction that incorporates 50% more Iso-elastic Fibers, NCP Tension Fibers for longer tension maintenance, and new PEEK abrasion resistant fibers woven within the outer wraps for enhanced durability. This unique construction combined with GAMMAs exclusive Advanced Irradiation Process provides Gut-Like Performance and a crisp, solid feel preferred by top professionals. Available in Natural. Available in Natural.