The submersible HAILEA Glass Heater is fully thermostatically controlled and is ideal for the heating of water in aquariums/fish tanks and nutrient in hydroponic tanks. The submersible automatic aquarium heater has an easily visible thermometer-style temperature indicator. The sensitive and reliable thermostat maintains a uniform temperature. Its heating element is highly efficient and compact. Hailea glass heaters are designed for extended use and complete safety and are also supplied with strong clips and suction cups . This product is a new highly advanced range of automatic heaters to meet the need for every aquarium. They are available in 100 watt, 200 watt and 300 watt varieties.