DescriptionRH80 Series thermo-hygrometers are compact in size and easily fit into your shirt pocket. The cover protects the sensor and also acts as a handy pocket clip. Model RH81 is a digital thermo-hygrometer with min/max data storage, data hold and auto power off features. Model RH82 has all of the features of the RH81 and also measures dewpoint. Model RH83 has all of the features of the RH81 and also measures dewpoint and wet bulb temperature.