This is the AirDog II-4G DF-165 fuel system for the 2015-2016 Duramax 6.6L Diesel. This system mounts to the frame jig in front of the fuel tank for a clean looking installation. The suction side hooks up to the factory suction fitting in the fuel module. The pressure side connects directly to the factory injection pump feed line on the frame. The AirDog Air/Vapor return is sent back to the tank through a filler neck tee. This system is one of our easiest installations. Our Duramax kits usually see the largest performance gains as these trucks do not come with a lift pump from the factory. This is a 165GPH (Gallon Per Hour) fuel system for moderately modified trucks.