The production of components of heat shrink fiber optic protectors, such as hot-melt or heat shrink tubes, requires the control of the humidity content in the granules. Granules tend to absorb humidity from the air. Humidity can be absorbed inside the granulate or it can collect as a result of condensation in the form of droplets on the surface. Its presence during the processing process may lead to surface defects or deterioration of mechanical properties. The presence of humidity in the granulate can only be determined with specialized measuring equipment. In our laboratory, we use the Kern DBS 60-3 Humidity Analyzer of the German company KERN & SOHN GmbH for this purpose. The device allows us to measure humidity in the range from 0 to 100% with an accuracy of 0.01%.