The Planet Waves Humidity & Temperature Sensor (HTS) provides key the 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 percent) to 99 percent. Temperature is displayed in both Farenheit or Centigrade ranging from -32F to 122F. A programmable set point monitors the minimum humidity desired. When humidity is below the set point, an icon 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 inches.