Heat Stress Monitor Relative Humidity Range 0 to 100 Percent Humidity Accuracy +/-3 Percent Temp Range (F) 32 Degrees to 122 Degrees Temp Accuracy (F) +/-1.8 Degrees Wet Bulb Temperature Range 32 Degrees to 122 Degrees F Wet Bulb Globe Temperature 32 Degrees to 122 Degrees F Black Globe Temperature -22 Degrees to 122 Degrees F Air Temp (F) 32 Degrees to 122 Degrees Air Temp (C) 0 Degrees to 50 Degrees Battery Type AAA Interface RS-232