Variations in climatic conditions can cause damage to your musical instruments. The Planet Waves Humidity & Temperature Sensor will provide key info to help maintain the proper climatic conditions to avoid such damage. The Humidity & Temperature Sensor is a precision-designed hygrometer that 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. The design includes a programmable set point that can set 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 can also indicate the highest and lowest temperature and humidity conditions your instrument has been exposed to, as well as the date and time of that high and low, since the last reset. Get one for each of your instruments. It is a wise investment to properly install and use a Planet Waves HTS and humidifier in each of your instrument cases.