Water temperature is an important factor that affects the health of fish. The Fluval vertical mount digital thermometer is easy to read and can accurately read temperatures ranging from 18 to 30 degrees C (64 to 86 degrees F). The thermometer comes with an adhesive backing that allows you to easily mount it to the aquarium glass. A genuine accessory for Fluval EDGE aquariums it is ideal for all fresh and saltwater aquarium setups. Size: 4.45 cm (1.75 in) length