Get precise control of your aquarium temperature with Marineland Precision Submersible Heater. With an adjustable temperature dial, high-visibility temperature display and an advanced heating element, this heater makes it easy to keep your freshwater or saltwater aquarium water at the optimal temperature. A flattened mesh heating element surrounds a mica core for superior heat transfer. Features a thermal safety switch that prevents heater failure during use the heater automatically turns off if the temperature rises above an internal pre-set and turns back on once it cools down. A mounting bracket is included to securely attach to glass.