Dretec Digital Wall-Mounted Thermometer, Indoor/Outdoor, Ivory

You can see the external and internal temperatures on one screen. It has a maximum and minimum temperature memory that can be checked with the "Max/Min" button. The external sensor at the end of the cord is waterproof, making it suitable for measuring the temperature of an aquarium. It comes with a hook hole, magnet, and stand, making it easy to use anywhere. The long 3m cord is designed to prevent breakage even when clamped to a window or refrigerator. This product requires batteries.