The Edgetech Instruments Model 625 humidity/temperature hand-held hygrometer can display any of the following: RH and temperature, or dew point and temperature, or wet bulb and temperature. The unit includes the 625 hand held hygrometer, an integral humidity probe head, a handle and cable, a 9V battery, a travel case and a NIST traceable calibration certificate. The Model 625 is an ideal instrument for indoor air quality (IAQ) and indoor environmental quality (IEQ) measurements of temperature and humidity. The EdgeTech 625 temp/RH probe can be used two ways: use it as an integrated unit by attaching the probe head to the instrument or connect both parts via a cable. The clear back-lit display can be switched between relative humidity, wet bulb, and dew point at the touch of a button.