This thermometer registers temperature, on the Fahrenheit scale, in your refrigerator or freezer. Two color codes (red & blue) indicate temperature at refrigeration and freezing points. Red flag on thermometer’s exterior gauges whether or not the freezing point is being maintained. Lets you monitor freezer temperature to help minimize freezer burn. Built-in hook facilitates hanging on rack or shelf. Made of polystyrene and glass. Measures approximately 5"l x 1"w x 1"d including hanger. Very accurate and great for food service environments, home, office, and anywhere food or beverages are being stored. Comes with 2 refrigerator/freezer thermometers.