The innovative X-Flow EVO Head Piston in Ertalon+mos2 (polymer) made with the CNC machining, has been designed and calibrated to the thousandth. Its particular concave shape without the presence of the front anti vacuum holes, ensures high efficiency during the compression phase, guaranteeing a perfect concentration of the air flow so as to be pushed and routed directly into the nozzle of the cylinder head, avoiding the formation of air vortices. This means greater accuracy and pinkish narrow, and an increase in the firing rate. The anti vacuum holes are present in the outer part and they are radial type. With this piston head you will improve output and precision and consistency of fire.