How to use: there are two keys on the back of the freezer thermometer, ON/OFF is the power switch, and you can turn the power on or off with one key The C/F key is the temperature measure conversion key, which can switch between Fahrenheit and Celsius with one key, suitable for different people in different regions The largest circular turntable is where the battery port is closed Do not open it at will . Temperature Range: The temperature range is from -20C / -4F to 60C / 140F provides crucial temperature readings for food safety applications. Ideal for the refrigerator that does not come with a temperature.. When the temperature is between 4.0C/39.2F~ 7.9C / 46.44F, you will see the Frost Alert on the Screen. . Large LCD display: our fridge thermostat is equipped with a high-definition digital large-screen display, you can easily read a display with large, bold numbers just by looking across the room, which is very suitable for people with poor eyesight and the elderly . Suspension design: the small thermometer sugar thermometer comes with a magnetic backrest, stand and suspension hook, providing you with 3 different placement options, you can use a rear magnet to stick it to the refrigerator door, or use a stand to place it on the table, and finally you can turn the stand upside down to use a hook hanging from the refrigerator shelf or refrigerator . Instruction provided: when you receive the digital freezer thermometer, there will be an English version of the product instruction manual attached to the package Please do not throw it out as garbage, if you cannot understand English well, you can refer to our product details page or product display pictures .