Made specifically for advanced & professional players, the Polyfibre Viper is a monofilament tennis string providing a great combination of power, shock absorption & shot precision. It ensures great spin potential, ultra-soft touch & enhanced control & features SMD (Standardized Molecular Distribution) technology for solid durability. To prevent string slippage & grab the ball better, the string has a special corona coating. It is very arm-friendly & comes as a set of 12.2m (40ft).