DEF, known as AdBlue® in Europe, is a urea-based reactive chemical designed specifically to be used in SCR (Selective Catalytic Reduction) systems to reduce NOx emissions and transform them into nitrogen and water. DEF was formulated with pure urea and deionized water to create a 32.5% solution.

DEF is used to address a wide variety of agricultural and environmental needs. It meets and exceeds ISO-22241.1, API, and OEM requirements, and relates directly to fuel consumption. It is expected that DEF is consumed at a 50 to 1 rate (50 gallons of diesel consumption will use up one gallon of DEF).