This is the AirDog II-4G DF-165 fuel system for the 2003-2007 6.0L Powerstroke. This replaces the factory frame rail fuel pump. This system mounts to the frame rail using the supplied sandwich plate mounting system. The suction side hooks up to the factory suction line on the frame rail. The pressure side connects to the factory feed line to the injection pump. The AirDog Air/Vapor return is sent back to the tank through a return “Y” that ties the AirDog return to the factory engine return. This is a 165GPH (Gallon Per Hour) fuel system for moderately modified trucks. Check out our installation manual for a list of parts that are included with this kit.