Heat Stress Meter Humidity / Environmental /HVAC / Temperature / Dew point / Wet bulb globe temperature / Surface temperature With the Heat Stress Meter it is possible to measure climate conditions such as temperature, relative humidity, and much more. Backlit LCD. Measures ambient humidity and temperature using an internal sensor. Measures surface temperature using an optional external sensor. Infrared measurement of a material temperature. Display shows temperature and humidity simultaneously. Average value, Maximum, Minimum and Hold functions. Auto shut-off to protect battery life