A thermocouple is a sensor that measures temperature. It consists of two different types of metal bonded at one end. A voltage is generated when the junction of two metals is heated or cooled. This also correlates with temperature.
Product Specifications LED display, Acrylonitrile butadiene styrene (ABS) material used, 295 grams weight, battery powered, 0.1 degrees celsius resolution, 149x71x41mm size, with upper-temperature rating of 1300 degree celsius.