The Extech IRT600-NIST-L is a Dual Laser IR Thermal Condensation Scanner. This 12:1 Infrared Psychrometer with 3-Color LED Dew Point Alarm measures temperature and humidity then calculates Dew Point and warns the user when conditions for mold growth exist. Great for processes that require surface temperature control and monitoring. Green LED changes to Yellow and then to Red as the surface temperature reading gets closer to and then equals the calculated Dew Point reading. Dual lasers indicate ideal measuring distance where the two lasers converge to a 1" target spot. With limited NIST Calibration.