Spring M120 Progressive winding and premium quality from SHS (ref. Super Shooter). Made from quality spring wire with a blackened surface under corrosion. Materials and the entire production process has been certified by the Japanese certification authority, which means high quality. Thanks to temperature modification will spring save its characteristics (tested with> 10 thousand shoots without change). High quality spring, comparable with brands like. Systema, Guarder, KM-Head, etc.