Aqueon Pro Aquarium Heaters are built to deliver consistent heat. Each unit is made with a durable thermal plastic shatterproof housing and equipped with an electronic thermostat. The thermostat has an auto shut off safety feature, when the top of the heater tilts below the bottom of the heater, it will shut off. Additional features include adjustable heat settings and LED heating indicator that illuminates when actively heating. The suction cups make horizontal or vertical installation quick and easy. Pro Heaters are fully submersible and made for use in freshwater and saltwater aquariums. Available in five sizes to accommodate various aquarium sizes. Adjustable heat setting 68 to 88?F, Electronic Thermostat accurate to /- 1?|Shatterproof construction|Fully submersible; Auto Shut-Off when over-heats, resets when it cools down|LED knob glows red when actively heating|Limited time warranty|Ideal for aquariums up to 100 gallons br/>Sold in Quantity of: 1