Extech RH401 Triple Display Hygro Thermometer Psychrometer with Built In Infrared Thermometer Item is a Class II laser product, 1mW power output. 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 Can locate potential mold problems by spotting surface temperatures below the dew point