The Acu-Rite Suction Cup Thermometer features a strong suction cup cling to mount on outside windows. The sensor displays the outdoor temperature in Celsius or Fahrenheit with a daily minimum and maximum temperature reading and current temperature reading. Powered by button cell battery, the suction cup thermometer is for someone interested in a basic digital thermometer. This indoor or outdoor thermometer gives you the temperature with daily high/low information in a contemporary, red tear-drop design. Simple, cool-looking and a great value, this thermometer is a must have.