HOME > EXTECH > THERMOMETERS > RH390 extech logo

Extech RH390
Precision Psychrometer

Highest 2% RH accuracy

  • Dual backlit display
  • Simultaneous display of:
    • Humidity/Temperature
    • Humidity/Dew Point
    • Humidity/Wet Bulb
  • Slim design with rubberized sides for better grip and for one hand operation
  • Data Hold and Min/Max functions
  • Auto power off with disable and low battery indicator
Click here for a larger image - Extech RH390 SuperHeat PsychrometerClick for larger image
Extech RH390 Shown

Product Information
Datasheet 91 KB
Ordering Info Jump to Product Models, Prices, Accessories, and Ordering Information
PDF Help
Humidity 0 to 100% RH
Temperature -4 to 140°F (-20 to 60°C)
Basic Accuracy ± 2% RH, ± 3°F/2°C
Max. Resolution 0.1% RH, 0.1°F/°C
Dewpoint -22 to 212°F (30 to 100°C)
Wet Bulb 32 to 176°F (0 to 80°C)
Dimensions 7.81x1.7x1.3" (200x45x33mm)
Weight 7oz (200g)
Ordering Information
Model Description Buy Online Price
RH390 Extech RH390 Precision Psychrometer Buy Now Sale $161.99
(Reg. $199.99)
RH390-NIST Extech RH390-NIST Precision Psychrometer with NIST Buy Now $324.99
Included Accessories
  • (1) Carrying case
  • (1) 9V battery

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