2 x 500W Aquarium Heater Anti-Explosion Submersible Fish Tank Water Adjustable ully submersible heaters work in any position (horizontal or vertical) to provide optimum aquarium water temperature. Safe and reliable in both fresh and salt water aquariums! Temperature range between 65F and 93F. Sensitive and reliable thermostat maintains uniform temperature Includes Two suction cups for mounting. Automatic shut off when the temperature is reached.