The AQUANEAT 3 Pack Aquarium Thermometer is perfect for keeping track of the water temperature in your fish tank. With a wide range of applications, this thermometer is ideal for use in water or high moisture environments like an aquarium terrarium or vivarium. The thermometer comes with a large LCD display that is easy to read, and it also has an easy-to-setup submersible probe that makes it quick and easy to take the temperature. The free LR44 battery cells are included so you can use this thermometer even without a power supply.