4.EASY TO INSTALL AND OPERATE: Use the magnet on the back to magnetically attach the thermometer directly to your refrigerator or freezer, or place it on a table. 1.Wireless signal transmission distance without interference 100 meters, can display two different maximum and minimum temperature records at the same time. 2.℃/˚F unit conversion: Celsius and Fahrenheit display can be switched to meet and has strong signal penetration. 3.ALARM SETTINGS: When the indoor or outdoor temperature exceeds the preset minimum and maximum alarm values, the thermometer emit an audible alarm and a visual alarm to alert you and allow you to see if adjustments are 5.APPLICATION: Can be used in the refrigerator, freezer or indoors and outdoors to easily monitor temperature changes and provide double protection for your food.