Review: Oasis OH-2C Digital Thermometer and Hygrometer Keeps an Eye on Your Guitar’s Environment

The OH-2C is a palm-sized, super slim unit with a pair of Velcro squares for easy mounting on any surface

Like all too many guitar owners, I paid no mind to humidity control—that is, until my near-mint 1930s Gibson L-4 developed a crack in its back during a particularly brutal New York City winter some years ago. Since then, I’ve kept obsessive tabs on the relative humidity level in the room where my wooden instruments are stored, a maintenance practice made easy with an old-school Abbeon hygrometer I scored on eBay.

While the relatively bulky Abbeon does a perfect job of monitoring the relative humidity in the room, a product like the Oasis OH-2C digital hygrometer/thermometer is an excellent option for measuring the conditions inside an instrument’s case.


The OH-2C is a palm-sized, super slim unit with a pair of Velcro squares for easy mounting on any surface, plus a clip for attaching it to the flap of an instrument case’s internal accessory compartment. With an effective humidity range of 20–100 percent, the OH-2C is said to maintain accuracy for years, and the unit comes with a five-year guarantee. The OH-2C also measures temperature in either Celsius or Fahrenheit and keeps track of high and low temperatures.

I live on the coast in the temperate climes of Northern California, and while I’m fortunate not to have to deal with dryness, I do use a portable dehumidifier to maintain an optimal humidity level of between 45 and 50 percent in the room where my instruments live. The level read by the OH-2C exactly matched that on the Abbeon. Though I didn’t see the need for calibration, the unit is adjustable in +/- 5 RH points with a recommended kit from Boveda, which at press time was available free with purchase of the OH-2C at the manufacturer’s website.

I tested the OH-2C with a cherished Collings archtop and was a little surprised by what I found: Inside the case the humidity level read 58 percent, which is of course higher than ideal. This was quite useful data to have. I now keep the guitar hanging safely on a wall outside of the case, where the humidity level is optimal—and where the instrument receives much more playing time.

PRICE: $29.95 direct

Adam Perlmutter
Adam Perlmutter

Adam Perlmutter holds a bachelor of music degree from the University of North Carolina-Greensboro and a master's degree in Contemporary Improvisation from the New England Conservatory. He is the editor of Acoustic Guitar.

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