General Tools WBGT8778 Deluxe Heat Index Monitor with Wet Bulb Globe Temperature, 75mm Black Ball The General Tools Deluxe Heat Index Monitor is an industry breakthrough for outdoor sports designs to monitor heat conditions This heat index monitor is ideal for industrial uses including HVAC/R and outdoor sports medicine applications Measures 4 parameter - wet bulb globe temperature, air temperature, relative humidity, and dew point; CE approved Temperature measurement range of 32 F to 122 F and wet bult temperature measurement range of 70 F to 115 F Item dimensions are 11 x 3 x 3 inches; Powered by 2 AAA batteries (included)