Health Canada recommends making sure your refrigerator is set at 4 °C (40 °F) or lower and your freezer at -18 °C (0 °F) or lower. This will keep your food out of the temperature danger zone between 4 °C (40 °F) to 60 °C (140 °F) where bacteria can grow quickly. Most refrigerators have built-in digital thermometers in the refrigerator, freezer, or both. However, it is always a good idea to check to see if your appliance is maintaining the temperatures you've set. Also, there are warmer and colder spots in the fridge and freezer and a standalone thermometer may be able to help detect those so you can organize your food storage accordingly.This AccuChef freezer/refrigerator thermometer is made of a durable stainless steel frame and high-quality glass lens.The temperature range of this thermometer is -20°F to 68°F (-30°C to 20°C) and the dial face is clear with both Fahrenheit and Celsius. It also has an optimal zone on the dial face to indicate whether the temperature is in the freeze, fresh, or spoil zone. This helps to easily identify ideal temperatures and avoid food spoilage and the buildup of bacteria and salmonella. The design of our refrigerator and freezer thermometer gives you the option to hang it in the oven with a hook or to leave it standing with the stand panel. A battery or power supply is not necessary to use this thermometer. AccuChef has a 2-year warranty on this thermometer.