Extech RH300 Digital Psychrometer, Humidity (RH), Air Temperature, Dew Point & Wet Bulb Meter;

Compact meter is ideal for field applications - it displays relative humidity and temperature simultaneously, and dew point or wet bulb or probe temperature on a large LCD. Features include a choice of readings in degF or degC, Min/Max, data hold, and auto power off. Unique sensor cap closes to protect the sensor during storage. Advanced features include the calculation of T1-T2 temperature differential with external temperature probe 37803-18 (sold separately). Unique sensor cap closes to protect the sensor during storage. Meter can be calibrated in the field using optional RH calibration standard salts. Order meter only or the complete thermohygrometer kit. 37803-10 includes two AAA batteries. Optional thermistor probe lets you calculate T1 - T2