DC battery powered, in 12V or 24V, makes these ideal for automotive applications. Switching fuel lines and thus fuel tanks makes them suitable for dual fuel or dual fuel tank systems like when running long range fuel tanks. 3 Port valves will change over a single fuel hose such as the supply line, while the Pollak 6 port valves will cross over supply and return lines, preventing cross contamination of the tanks. Various fittings sizes available. Great for vegetable oil conversions and compatible with biodiesel, SVO, UVO, diesel and petrol.