The Testo 0563 6251 Hygrometer with Integral Humidity Probe Head is a compact hygrometer designed for one-handed operation with a built-in humidity probe head and a large, backlit digital display that shows humidity, dew point, and temperature. The humidity measurement range is 0 to 100% relative humidity (RH) with a resolution of 0.1% RH and an accuracy of + or -2.5% RH within 5 to 95% RH. Temperature measurement range is -10 to +60 degrees C with a negative temperature coefficient (NTC) type probe and -200 to +1370 degrees C with a Type K (NiCr-Ni) probe (temperature probe not included). A hold function freezes readings on the display and max./min. values assist with data readout. The meter uses a 9V battery block (included) with an estimated battery life of 70 hours.

Hygrometers measure the moisture content, or humidity, in the environment, either as relative humidity (percentage of moisture in the air) or as absolute humidity (amount of moisture in the air). Some hygrometers can also measure temperature, dew point, and pressure. Handheld hygrometers are compact devices that use attached probes to take measurements and have a digital screen to report measurements. Other hygrometers utilize transmitters to send measurements from probes placed in ducts or outside environments to an output device; one example of this type is a weather forecasting hygrometer. Hygrometers are used in laboratories, storage areas, greenhouses, saunas, humidors, industrial and residential settings, and museums. Hygrometers can form part of devices called humidistats to help control humidifiers or dehumidifiers to regulate the humidity of the air.

Testo manufactures portable test and measurement instruments. The company, founded in 1957 in Germany, has a U.S. office in Sparta, NJ, and meets International Organization for Standardization (ISO) standard 9001.

What's in the Box?

• Testo 625 measuring device
• Plug-in humidity probe head
• 9V battery
• Calibration protocol