Portable Heat Stress Monitor measures humidity, temperature and radiant heatOn-board humidity sensor displays relative humidity and calculates heat index or humidex Portable Heat Stress Monitor calculates and displays WBGT indoors and outdoors. Features multilingual display and real-time relative humidity readings measured with RH sensor. ±0.5°C (0.9°F) temperature accuracy; ±5% relative humidity accuracy. –5° to 100°C (23°–212°F) sensor assembly temperature range; –5° to 60°C (23°–140°F) electronics temperature range. Includes wet bulb reservoir, shielded dry bulb, removable sensors for remote applications, 2" globe and 150-hour 9V battery. Measure 9.2" x 7.2" x 3" and weighs 2.6 lb.