The HygroLog HL20D series are data loggers for relative humidity, temperature, dew point and frost point monitoring. These loggers have integrated temperature and humidity sensors with an internal memory for up to 20,000 date and time stamped readings. Units are available with a display and are powered by 3 x AA batteries. These unit are ideal for use in pharmaceutical clean rooms, storage facilities, manufacturing areas, buildings, museums or any other critical area. Operating ranges ...