The Underwater Treasures Digital Thermometer gives an accurate reading and features an easy-to-read green indicator, so you'll always be sure your tank is at the correct temperature. It displays temperatures in both Fahrenheit and Celsius, taking out the guess work, and offers a range of 18-34°C and 64-93°F. The thermometer adheres directly to the tank's exterior and is ideal for both freshwater and saltwater aquariums. You can rely on The Underwater Treasures Digital Thermometer to offer a precise reading each and every time, giving you peace of mind that your tank is set at the correct temperature, which results in creating a comfortable atmosphere for your fish while protecting your tank from fungus and other water issues. This thermometer is not only dependable, it's affordable, so trust Underwater Treasures to monitor your tank's temperature.