★ 【Temperature range】59°F~94°F, display Fahrenheit °F, this heater is designed for10~20 gallons tank. Upgrade function: The heater will auto shut off when it is out of water and turn normal when fully in water again. ★ 【Automatic constant temperature function】 when water temperature reaches to specified temperature value, heater will automatically stop heating, when water temperature is lower than the set temperature, heater will automatically start heating. ★ 【Touch button】 cyclic adjust temperature , easy to use and Safety. ★【Note】:this heater is 100% submersible use only, during its heating time, heater must be 100% submerged into the water. ★【 satisfaction guarantee】Gain confidence and work with us! Our aquarium heaters are based on the concept of durability and the safety of each design. If you are not satisfied with our products, please contact us and we will be happy to provide you with a new replacement for aquarium heaters. 12-month warranty and 24-hour professional after-sales service.