• RH25
  • Manufacturer has 50 in stock
    This stock is typically available to ship in 3 - 5 working days.



  • Built-in multiparameter sensor
  • Ranges:
    • Temp; -4 to 122°F (-20 to 50°C)
    • RH; 0 to 99.9%RH
    • Wet bulb; -4 to 122°F (-20 to 50°C)
    • Dew point; -108.4 to 122°F (-78 to 50°C)
    • Heat index; -50.8 to 401°F (-46 to 205°C)
    • WBGT; -13 to 130°F (-25 to 54.5°C)
  • User Programmable Heat Index/WBGT alarm
  • MIn/Max/Average
  • Data Hold
  • Auto power off with disable
  • Complete with CR2032 battery


The Extech RH25 Psychrometer is a pocket-sized heat index psychrometer pen that easily monitors heat index during hot humid days to prevent heat stroke during outdoor activities, sporting events or, indoor workplace. Its pen-sized design makes it convenient to fit into your pocket and carry it wherever you go. Heat Index measures how hot it feels when humidity is combined with temperature, air movement, and radiant heat. Wet Bulb Globe Temperature (WBGT) considers the effects of temperature, humidity, and direct or radiant sunlight. The RH25