Now you can measure the relative humidity right in your classical guitar case and know when to use your guitar humidifier. I use this one myself.

Acoustic Guitar Humidifier by Planet Waves
The Planet Waves Humidity & Temperature Sensor (HTS) provides the key info you need to help maintain proper climatic conditions to avoid instrument damage.

The HTS digitally indicates accurate relative humidity levels ranging from low (under 20%) to 99%. Temperature is displayed in both Farenheit or Centigrade ranging from –32oF to 122oF.

A programmable set point monitors the minimum humidity desired. When humidity is below the set point, an icon (water drop)will indicate it is necessary to use a humidifier. The high and low memory indicates the highest and lowest temperature and humidity levels your instrument has been exposed to, as well as the date and time of that high and low, since the last reset.

Product dimensions: 4" x 2.75"

YOUR PRICE: $35.95
The suggested list price is $49.99

Feel free to give me a call toll free at 1-866-827-7342 or 607-387-3875 with any questions or to order a guitar. I enjoy talking about guitars. Or e-mail me at tom@pavanguitars.com.