Introduction The TRH22 is a laboratory grade instrument to measure relative humidity and temperature. Its extended probe allows the user to make measurements inside ducts or hard to reach areas. The Relative and MIN/MAX functions enable measurements to be made in two different areas and then compared. The large dual display and Data Hold function both make viewing the measurement results convenient. Measure temperature in °C or °F with tenth percent resolution. The TRH22 utilizes a capacitive sensor for humidity measurements up to 100% with a tenth percent resolution. With an auto power off feature to save battery life, protective cap for sensor life, vinyl carry case for transportation and battery installed, the TRH22 is the right choice for your atmospheric humidity measurement needs.