The Triplett RHT45 Digital Psychrometer measures Air Temperature, Relative Humidity, Wet Bulb, Dew Point, and Type K Temperature and is ideal for building inspection, water restoration, greenhouses, warehouses, museums, libraries, offices, and storage areas. For HVAC Technicians, specialized modes include NORMAL Psychrometer Mode, Target Superheat Mode (TSH) and Target Evaporator Exit Temperature Mode (TEET). It features Min/Max 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.