A thermometer is a device that measures temperature (how hot or cold an object is). The two building blocks of a thermometer are: (1) the temperature sensor (e.g. the bulb of a glass mercury thermometer or the pyrometric sensor in an infrared thermometer) where a physical change occurs relative to the temperature at which undergoes; (2) the instrument, which converts the physical change of the sensor into a numerical value (displayed on the display or on a smartphone application). Thermometers are widely used in technology and industry to monitor processes, in meteorology, in medicine and in scientific research. We offer the instruments from Testo, the world leader in measurement technology.