5 Packs High-tech Synthetic Gut Tennis Racquet String 80% premier grade natural gut ,10% carbon nanofiber and patented high-tech fibre, apply thermal tenology  a process of high temperature finishing that increases the cohesion of the fibre down to the core of the string. Connect series of nano-elements with the carbon nano-fiber, natural fibre and patented fibre. The life of string increased by 76%. The surface of string applied titanium hydride patented glue, to provide superior feel and high durability Great waterproofOxidation resistant packaging to maintain the best performance long line to provide maximum strength and feel. Gauge: 16 / 1.30mm Length: 40 feet / 12.2m Composition:Premier grade natural gut+carbon nanofiber+ Patented high-techfiber Color: Natural Made in Taiwan