Urea Refractometer for Testing Urea-Based Diesel Exhaust Fluid (DEF / AdBlue) Concentration in Selective Catalytic Reduction (SCR) Equipped Diesel Engines The DEF-201 will DEFeat those seeking to DEFraud Diesel Exhaust Fluid (DEF) is already a reality for trucks, buses, and highway vehicles powered by diesel engines. In 2014, new Tier IV guidelines go into effect for off-road equipment as well. These regulations will affect excavators, bulldozers, skid steers and other commercial construction equipment. Also affected are farm tractors and agricultural equipment, heavy forklifts, and airport ground service equipment. Even diesel powered stationary equipment such as generators, pumps, and compressors will be required to meet emission requirements. To comply with EPA regulations, engine manufacturers are using Selective Catalytic Reduction technology which requires a very precise concentration of liquid urea (DEF) in order to operate properly. Selective Catalytic Reduction systems utilize liquid urea, a nitrogen-based compound, to treat diesel exhaust gases prior to them entering a special catalytic converter. The fluid is known as Diesel Exhaust Fluid (DEF) in the US and AdBlue in Europe. It consists of a very specific concentration of aqueous urea in demineralized water. Injected into the hot exhaust gases as a fine mist, urea turns to ammonia and converts harmful nitrogen oxides (NOx) into harmless nitrogen and water vapor. Brand New! Fresh from the Factory! The MISCO DEF-201 digital refractometer is the ideal method for testing and monitoring the concentration of urea-based Diesel Exhaust Fluid (DEF or AdBlue) required by diesel engines equipped with Selective Catalytic Reduction (SCR) technology This refractometer has a single scale for DEF concentration. Resolution: 0.1 Precision:0.1 Temperature Range 10 to 45 C (50 to 113 F) Made in the USA, Cleveland to be exact!