Preset Temp: This small fish tank heater Preset to 77°F, no adjustment or thermometer required, Prefect for 3-10 gallon fish tank with hoods or glass canopies. Safety Design: This small fish tank heater comply with the Standard for safety for Electric aquarium equipment UL1018, ensure 100% protection for your fish. The heating element surrounded by Corrosion resistant enclosure, it is durable, explosion-proof, shock-proof and resistant to burns. Smart Control: The heating element adopted intelligent circuit board, with a precise sensing probe and electric thermostat system, it will automatically turn on/off to achieve the preset temperature constantly and stably. Mini Design: Its small footprint makes it easy to conceal behind plants or other décor. The aquarium heater can be completely submerged and fastened on the aquarium vertically or horizontally via strong grip suction cups Fish's Favorite: This Betta Fish Tank Heater have certificated for UL1018 certification, ETL certification, FCC certification, it can work in both brine and fresh water. Suitable for all kinds of aquarium pets like Betta, tropical fish, goldfish, ornamental fish and turtles.