These submersible heaters can be used in fresh or saltwater tanks. They all feature a unique reflective technology that maintains the natural look of your aquarium. Available in a wide variety of sizes to fit most tanks. The Fluval M series submersible glass heaters are quality manufactured in Europe using superior components and construction. These sleek, compact heaters can be trusted for exceptional performance and unsurpassed reliability. Unique only to the Fluval M series is the reflective technology which helps maintain your aquarium's natural look as the heater reflects the colors of the surroundings. For use in fresh and saltwater tanks. Manufacturer offers a 3 year warranty. Features: Easy to adjust temperature dial. Exclusive slim profile tube. Reflective technology maintains your aquarium's natural look as it reflects the colors of the surroundings. Shock resistant borosilicate glass. Cool blue on/off indicator lamp. High density Ceramic Heat Sink extends heating efficiency. Exclusive sealing system protects against water penetration. High temperature silver nickel pointed thermostat for extended accuracy and service life. Long life suction cups. Safe for fresh and saltwater use.