XIANQI Power source Battery Powered Number of batteries 1 Unknown batteries required. Minimum storage temperature 30 Degrees Celsius Upper temperature rating 60 Degrees Celsius About this item Smart Design: Quartz accuracy and waterproof material, which makes you use very convenient. Lightweight and small size will not take much room of your Refrigerator. Big digits, ideal for those people with poor eyesight. You can easily read the display with its big, and bold digits. Easy to Operate: No complicated controls, it is the simplest electronic thermometer with only two buttons. Press the on/off button to switch the thermometer on and then select Degrees or Fahrenheit. Temperature Range: The temperature range is from -20°C / -4°F to 60°C / 140°F provides crucial temperature readings for food safety applications. Perfect for the refrigerator that does not come with a temperature.. When the temperature is between 4.0°C/39.2°F~ 7.9°C / 46.44°F, you will see the Frost Alert on the Screen. Magnetic Back, Stand and Hook for Hanging: You have 3 different choices for placement for the room thermometer. Either stick it to the refrigerator door with the rear magnet, or use the stand to place it on the table-top, and finally you can flip the stand over and use the hook to hang it on a refrigerator shelf. Wide Range of Applications: Perfect thermometer for fridge, freezer or as a general room thermometer. It is useful for different occasions such as home, restaurants, bars, cafes. It is also a wonderful gift for your family or friends.