This is a rectangle 41 gallon diamond plate aluminum diesel auxiliary tank with Fuel Shotz installation kit for GM trucks up thru 2010. This auxiliary tank and install kit meet the necessary DOT requirements. This Fuel Shotz system connects the auxiliary tank to the factory tank via the factory fill neck hose. This system keeps the factory tank full until the auxiliary tank is empty. The Fuel Shotz installation system is quick and easy to install with no wires or switches necessary.