The Extech RH305-NIST Kit includes RH300 humidity meter, external temperature probe, 33% and 75% humidity calibration standards, and batteries. The meter simultaneously displays relative humidity, air temperature and dew point or wet bulb. Can also measure external temperature measurement using the temperature probe supplied in the kit. Compact meter is ideal for field applications. Unique sensor cap closes to protect to protect meter during storage. Advanced features include data hold, selectable auto power off, and MAX/MIN/Average reading. The meter can be calibrated in the field using the 33% and 75% humidity bottles supplied in the kit. A hard case is included for storing the calibration bottles when not in use. With NIST Calibration.