Proper humidity levels can not only make your guitar sound its best, but also prolong the life of your instrument. This D’Addario Humidity and Temperature Sensor features an accurate digital temperature indicator in Fahrenheit (-32 degrees F to 122 degrees F) or Centigrade (-35 degrees C to 50 degrees C). There’s also an accurate relative humidity indicator (20% to 99%, under 20% displays the word “Lo”), that will indicate when you need to use a D’Addario instrument humidifier to raise humidity level in your instrument case. High and low temperature memory indicates the highest and lowest temperature and humidity conditions your instrument has been exposed to since the last reset. The D’Addario Humidity and Temperature Sensor is a great way to monitor the humidity health of your acoustic instrument.