Sim Works SP31 Inner WireSP31 Inner Wire made by Nissen Cable. A fine standard in bicycle wire technology. 31 wires, which are more than a typical 19 wires, are assembled via the Warrington" method, formed by high density wires and each wire has different diameter. More wires decrease spaces between them and enhance the rigidity of stretching direction, and at the same time earns high flexibility. A tensile strength is 10% higher than a similar product. Engraving the surface