BlueDEF DEF002 Diesel Exhaust Fluid - 2.5 Gallon Jug One gallon of BlueDEF is used approximately every 300 miles A truck with a 20 gallon DEF tank can go up to 6000 miles between fill-ups When used in an SCR system BlueDEF will reduce the levels of NOx emissions of those engines Non-flammable Diesel exhaust fluid