The Planet Waves Humidity & Temperature Sensor (HTS) provides key info you need to help maintain proper conditions to avoid damage to your instrument. Temperature is displayed in Fahrenheit or Centigrade ranging from -32 degrees F to 122 degrees F. The HTS digitally indicates accurate relative humidity levels ranging from low (under 20%) to 99%. A programmable set point monitors the minimum humidity desired. When humidity is below the set point, a water drop icon will indicate it is necessary to use a humidifier. The high and low memory indicates the highest and lowest temperatures and humidity levels that your instrument has been exposed to, as well as the date and time of those highs and lows since the last reset. Product dimensions: 4" x 2.75"