HTC IRX-66 -50-1550C Infrared Thermometer measures the temperature at any distance up to 30:1 Contact Sensor. Accuracy ±1.5% of reading. Range -50° to 1550°C ( -58° to 2498°F ). The HTC IRX-66 -50-1550C Infrared Thermometer is a professional infrared thermometer that is ideal for indoor and outdoor use, as well as for industrial applications, particularly for measuring ambient temperature or hot surfaces.