Fluval 2-in-1 Wireless Digital Aquarium ThermometerWater temperature is an important factor that affects the health of fish. The Fluval wireless 2-in-1 Digital Aquarium Thermometer allows you to accurately monitor water and room temperature simultaneously.It is easily mounted to the outside of the aquarium glass, avoiding the need for unsightly probes or wires.Easy-to-use digital thermometer:2-in-1 design measures and communicates water and room temperature within 1°C (2°F)Large, easy-to-read LCD displayWireless – easily mounts to aquarium exterior glass with no need for probes or messy wiresCelsius or Fahrenheit temperature selectionsCan be used for coldwater, freshwater, or saltwater aquariumsWhat kind of battery does this thermometer use?The Digital Aquarium Thermometer uses an LR44 cell battery and is included with the thermometer.