With the HT30 Wet Bulb Globe Temperature (WBGT) meter, you can measure the heat stress index or how hot it feels when humidity is combined with temperature, air movement and radiant heat. The meter can also take individual measurements of temperature, humidity and radiant heat and monitor the effects of direct sunlight on a sun-exposed surface using the Black Globe temperature sensor. An on/off function displays the WGBT reading with or without direct sunlight. Other functions include automatic shut-off with override and an integrated RS-232 interface. Incl. two AAA batteries.