This is a genuine component which is supplied by the original equipment manufacturer. It is specially designed for use with Chicago Pneumatic impact tools. It fits inside the cylinder assembly in order to move the air. This is an identical replacement for a missing or a faulty blade-rotor that was installed on a new unit. Make sure to ref...Read moreer to the owner's manual and the diagrams for your model for the correct repair process. Keep in mind this high-quality blade-rotor is made of durable composite material and is sold in a set of four.