OH-2+ Digital Hygrometer / Thermometer

OH-2+ Digital Hygrometer / Thermometer



Product overview

The OH-2+ is the latest version in the OH-2 hygrometer product line. It has a new digital sensor that im-proves the accuracy of the hygrometer to +/- 3% between 20% – 80% RH. The hygrometer also has an ex-tended reading range down to 10% RH rather the 20% RH on the previous two models. This eliminates the annoying “LL” sign one the display when the humidity drops below 20% RH. The increased range will help those users in extremely dry areas to get a more accurate reading of their humidity.

The humidifier has the same size and look as previous versions. The calibration feature is also included, but shouldn’t be necessary with the improved accuracy. If calibration is desired, you first need to get a Boveda one-step calibration kit. They come in 32 and 72% calibration levels. Place the OH-2+ in the pouch and let the hygrometer wait overnight in the bag. The humidity in the bag will be either 32 or 72%. If your hygrometer reads differently, figure out the % difference. The hygrometer can be adjusted up or down by 6%. Push the upper set button and hold for 5 seconds until is starts blinking. Push the min/max button repeatedly. The % change will start at 0 and move up to 6. If you keep pushing, the next number will be -6% and it will go down to 0 by continuing to push the min/max button. Whatever you calculated was the percentage difference between -6 and +6% is shown on the screen. Press the set button and the display returns to normal but is adjusted for the difference you entered in the processor.

Don’t forget the OH-20 hygrometer holder that allows you to place the hygrometer near the sound hole for accurate RH readings.


  • Measures temperature in degrees C or F with the range of 32-125 degrees F
  • Min-Max memory for both humidity and temperature
  • For indoor use only. Uses a CR2032 battery
  • Accuracy +/- 3% between 20-80%.
  • User Manual (Download here)

$29.95 plus shipping