The Fluval "M" 50 watt submersible heater is quality manufactured in Europe using superior components and construction. This sleek, compact Fluval heater can be trusted for exceptional performance and unsurpassed reliability. Unique only to the Fluval "M" series the reflective technology helps maintain the aquariums' natural look as the heater reflects the colors of the surroundings. The heater is ideal for 15 US gal (50L). aquariums and can be used in fresh and saltwater tanks.