AdBlue is a liquid solution consisting of 32.5% high purity urea (CO(NH2)2) and 67.5% deionized water and is synthetically produced from ammonia (NH₃) and carbon dioxide (CO2). 

It is a non-flammable, non-explosive, and environmentally harmless liquid and can be safely transported. With urea as the main "active" ingredient, AdBlue converts up to 85% of the harmful nitrogen oxides (NOx) from diesel vehicle exhaust gases into harmless nitrogen and water vapor and enables diesel engines in cars to meet the strict Euro 6 emission standards.

The PCE-DRU 1 refractometer is a precision measuring instrument that determines the refractive index of a liquid and ensures maximum reliability even under complex measuring conditions. Even when only a small sample is available, the user can measure the urea concentration.

To determine the urea value, just a few drops of AdBlue on the stainless steel plate of the device are sufficient. The sample plate contains a prism enclosed in the stainless steel holder, and thus, through light refraction, the urea content is measured. The measurement result is displayed quickly and accurately on the large, easy-to-read LC screen of the refractometer after automatic temperature compensation (10 to 40 °C). The user can select between two measurement parameters: urea (NH2) / AdBlue (2CO) (0 to 51.0%) and refractive index (1.3330 to 1.4056 nD). Additionally, the measured temperature of the liquid is displayed. The glass prism of the refractometer can be quickly and easily cleaned before and after measurement and is protected by a plastic cover from wear. To save the meter's battery, the refractometer automatically switches off after one minute of inactivity. The user can easily and quickly calibrate the refractometer using a few drops of deionized water.