The Infrared Thermometer Model CA879 is a non-contact temperature measuring instrument. It provides precision measurement with its laser target feature.. To measure the temperature of an object, simply point the gun at the surface of the object and the temperature will appear on the digital display. The thermometer has an automatic shut-off feature. Shut-off will occur approximately 10 seconds after the trigger is released.. All objects whose temperature is higher than absolute zero (-273.15 K) emit infrared energy. This energy radiates in all directions at the speed of light. When the gun is pointed at an object, the probe ‚¬ „¢s lens senses this energy and focuses it onto an infrared detector comprised of a thermocouple stack. The detector produces a voltage signal proportional to the amount of energy received, and therefore proportional to the object ‚¬ „¢s temperature.. Certain objects emit infrared energy, but also reflect it. Unlike matt surfaces, shiny or highly-polished surfaces tend to reflect energy. This reflection is represented by a factor called emissivity, which may vary from 0.1 for a highly reflective object to 1 for a black object. In the case of the Infrared Thermometer Model CA879, the emissivity is preset at 0.95, the most frequent value, enabling approximately 90% of all applications to be covered.