Extech RH405 Psychrometer, InfraRed Thermometer, Humidity Meter, RS232 Computer Interface, and Calibration Standard Combo Kit Built-in IR thermometer with laser pointer measures surface temperature from -40 to 932F (-40 to 500C) Displays air temperature, humidity and surface temperature or dew point, humidity and surface temperature or wet bulb, humidity and surface temperature on a triple LCD with backlighting Calculates the temperature difference between IR surface temperature and dew point Calibrate the meter in the field using the 33-percent and 75-percent calibration standards supplied with the kit Includes PC cable for downloading readings to a PC