Extech RH390 Precision Dual Display Hygro Thermometer Psychrometer Measures relative humidity from 0 to 100% and temperature from -4 to 140 F (-20 to 60 C) Accuracy 2% from 20% to 90%; 1.8F (1C) Dual display of humidity and temperature or humidity and dew point or humidity and wet bulb Capacitance sensor responds under to humidity changes in under 30 seconds Slim design with rubberized ides for better grip