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HM40 Thermo Hygrometer w/ Fixed Probe

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  • Incorporates Vaisala HUMICAP® sensor technology
  • Multilingual user interface available in 10 languages
  • HM40 requires two AA batteries
  • Includes belt clip and case
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Product Information

HM40 has a large, user-friendly graphical display and easy-to-use push buttons. Many settings can be modified to meet users’ individual needs. In addition to relative humidity and temperature, HM40 provides five calculated humidity parameters, all of which are available in metric and non-metric units. HM40 is powered by 2 AA batteries. An external USB-charger and rechargeable AA sized NiMH batteries are available as an option. Humidity measurement range 0 to 100 %RH.


  • Temperature measurement ranges 40 to 212 °F
  • Incorporates Vaisala HUMICAP® sensor technology
  • Calibration reminder function
  • Probes can be user calibrated using an on-site reference
  • Graphical display indicates when measurement has stabilized
  • Hold-button to freeze the screen and save the reading
  • Multilingual user interface available in 10 languages (EN, DE, FR, JA, ZH, PT, ES, RU, FI, SV)
  • Measures:

  • Dew Point
  • Wet Bulb Temperature
  • Absolute Humidity
  • Mixing Ratio
  • GPP 
  • Enthalpy
  • Calibrating HM40 is easy. The meter or the probe can be sent to a Vaisala Service Center for recalibration. Alternatively, calibration can be completed on site by users with a humidity reference such as another hand-held meter or Vaisala Humidity Calibrator HMK15. The indicator includes a calibration reminder function that can be activated by the user.



    More Information
    Thermo-Hygrometer RH Accuracy +/- 1.5 %
    Brand Vaisala
    Thermo-Hygrometer Temp Range -40 to 212 °F
    Thermo-Hygrometer Calculations GPP
    Category Thermo-Hygrometer
    Condition New
    Manufacturer Model Number HM40-A1AB