Li-Ning's No.1 Boost string promises 'Extreme Repulsion Power'. The string comprises three components, the core, the outer layer, and a coating on top of it. The core is made of thousands of strands wounded together to provide you with a heat resistant and high-intensity string. It also uses nano-technology for braiding the strings to provide maximum power and durability. The outer layer is also made of heat resistant and high-intensity nylon, which ensures that tension is evenly spread throughout the racket. The synthetic resin provides a case and a coating for the string and ensures elasticity for better performance.