The advanced 4G technology offers protection and performance like never before! Our patented air separation, along with a water separator and fuel filter makes sure your expensive injection system components get all the clean fuel they need. The AirDog® II-4G also overcomes loss of power due to driving in higher altitudes. The AirDog® II-4G System Improves Engine Performance by eliminating spray pattern disruption due to air entering the system. This allows the engine to keep its designed injection timing which allows a more complete burn of the fuel entering the cylinder. This increases overall engine efficiency across the power and torque range!