|Model 8145 Thermo-Hygrograph records precise measurements of temperature and humidity. The Durotherm sensing element for humidity will not dry out or get brittle with age, but will go on year after year. The humidity sensor is temperatureåÑ compensated by a bimetallic strip which eliminates the expansion of the Durotherm elements due to temperature variations. Lufft’s Thermo-hygrographs differ from other manufacturers’ units in this respect. The humidity arm is actuated by the sensing element to record minute changes in humidity. The bimetallic temperature sensing element actuates the arm that records small temperature changes. Easily calibrated. Can be certified to NIST.|
Recording Pens: Long-writing felt tipped nibs (two included)
The Model 8147R records precise measurements of both temperature and humidity. The Durotherm sensing element activates the arm that records the humidity and the bimetallic temperature spring activates the arm that records temperature. Easily calibrated. Quartz clock powered by one “AA” Battery. Revolution: Can be set for either 24-hr, 7-day, or 31-day.