Hagen Marina Compact 25W Aquarium Heater.
The Marina C25 Heater is a 25-watt compact, submersible heater for use in indoor aquariums. It is designed to reach and maintain the set temperature of 78 degrees Fahrenheit, without any adjustments. The exterior is made of a tough polymer so that it will not crack or break like traditional glass sleeve heaters. The heater is ideal for aquariums up to 6.6 gallons and can be used in fresh and saltwater tanks.