Hygro Thermometer Psychrometer, 0 Percent to 100 Percent Relative Humidity Range, +/-3 Percent Humidity Accuracy, -40 Degrees to 122 Degrees Temp. Range (F), +/-(0.5 Percent of reading + 2.0 Degrees F) Temp. Accuracy (F), 41 Degrees to 140 Degrees F (5 Degrees to 60 Degrees C) Wet Bulb Temperature Range, -40 Degrees to 176 Degrees F/-40 Degrees to 80 Degrees C Dew Point Range, 0.1 Percent Humidity Resolution, Display LCD, Battery Type 9V, Auto Power Off Yes, Data Hold Yes, Data Logging No