The Triplett Model RHT05 Hygro-Thermometer Pen measures Air Temperature, Relative Humidity, Wet Bulb, and Dew Point and is ideal for field applications including building inspection, water restoration, greenhouses, warehouses, museums, libraries, offices, and storage areas. It features a dual display that simultaneously displays Humidity and Air Temperature, or Wet Bulb, or Dew Point, °F/°C switchable readout, Minimum/Maximum mode for recalling the highest and lowest readings, Data Hold freezes the display for easy viewing, and Auto power off with disable to conserve battery life, and a built-in Humidity calibration procedure using optional calibration solutions. Includes a CR2032 battery. 1-year warranty.