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Extech RH401 and RH405 Kit
Psychrometer and Infrared Thermometer

Infrared for Non-Contact Temperature Measurements

  • Triple display with backlighting
           View Air temp+RH+surface temp
             View Dew Point+RH+surface temp
             View Wet Bulb+RH+surface temp
  • InfraRed Thermometer with
           Built-in laser pointer
             8:1 distance to target ratio
             Adjustable Emissivity from 0.3 to 1.0
  • Precision humidity capacitance sensor is retractable for
    protection during transportation and storage
  • Calculates T1 (IR Surface Temperature) - DP (Dew Point) differential
  • Programmable Auto power off and Low battery indication
  • Over-range/under-range alert indicator
  • Built-in RS-232 interface for capturing readings on a PC
  • RH405 kit includes RH401, 33% and 75%
    calibration bottles, PC cable, and carrying case
Click here for a larger image - Extech RH401 Psychrometer + Infrared ThermometerClick for larger image Click here for a larger image - Extech RH405Click for larger image
Extech RH401
Extech RH405
Product Information
Datasheet 156 KB
Manual 196 KB
PDF Help


  • Monitor Wet Bulb, Dew Point, Relative Humidity and Temperature in factories, clean rooms, offices, and greenhouses
  • Non-contact InfraRed surface temperature measurements in hard to reach areas such as heating and air conditioning duct
  • Humdity monitoring in schools, offices and manufacturing or storage areas
Ordering Information
Model Description Buy Online Price
RH401 Extech RH401 Psychrometer + Infrared Thermometer Buy Now Sale $149.99
(Reg. $199.99)
RH405  Extech RH405 Psychrometer + Infrared Thermometer Kit  Discontinued
Included Accessories
  RH401 includes:
  • 4 - AAA batteries
  • 1 - Carrying case

RH405 kit includes:

  • 1 - 401 meter
  • 1 - RS-232 cable
  • 4 - AAA batteries and carrying case
  • 1 - Set of 33% and 75% calibration bottles
Optional Accessories
589260  Extech 589260 RS232 PC CABLE FOR RH401 and RH405   Discontinued
RH401CAL Extech RH401-CAL, Humidity Solution Kit, 33% and 75%   Discontinued

*NOTE: Items ordered with optional NIST calibration will require
approximately 10 days to complete the certification.