Aqua Zonic Eco Aquarium Heater 25W Aqua Zonic ECO Heater is a fully automatic heater with adjustable temperature settings. It ensures water temperature is consistent and that heat is evenly distributed throughout. Easy to use even for novice fish hobbyists. Features Automatically maintains the selected temperature throughout the tank. Reliable construction and quality guarantees effectiveness Temperature dial is easy to read and set. Glass tube is specially toughened against heat and impact. Visible ON/OFF indicator lamp. Totally submersible in tank. Adhesive suckers and clip are provided to keep heater in place. Suitable for tropical or marine tanks.