Set of super high torque gears with helical teeth (100:300) from SHS. Important parts are made by CNC from steel. Gears with silent gear ratio and resistant helical teeth. The manufacturer states it is to be used on springs M120-M170, but in practice we have witnessed greater on even the strongest springs. In the gun can be used classic piston with full teeth, which is another big advantage. Unbeatable price/performance ratio.