Small yet powerful, the mini 25-watt Marina Submersible Aquarium Heater provides reliable heating for fresh or saltwater aquariums up 5.5 US gallon aquariums. The heater includes many practical features for easy use, safety and convenience, including an easy-to-access temperature set dial, on/off pilot light indicator and a bumper guard for fish safety. Made of durable high-impact glass, it"s built to last under normal aquatic conditions.