【Automatic Constant Temperature Intelligent Heater】The heater is made of explosion-proof quartz glass material and a high-temperature resistant nickel-chromium heating wire with silicon carbide heat conduction, fast water heating, and long-lasting 2 hours heating. The protecting jacket is a high-temperature resistant PC material, which can protect the fish and plant from scalding effectively. 【Visible Temperature Setting】The controller is not waterproof, please keep away from water，LED digital display screen shows the current water temperature and preset temperature. The number above the controller is the current water temperature, and the number below is the set temperature, Red light means heating, Blue lights indicate constant temperature, blue light flashing indicates the heater is not fully submersible. 【Temperature Adjustment feature & Automatic Heating】Temperatures Ranges 59℉ to 93℉, The heating rod built-in thermometer, When the water temperature is lower than the set temperature, the heater will automatically heating up, and stop heating when the water temperature is consistent with the set temperature. Fahrenheit and Celsius can be converted to each other, Pressing and holding for 5 seconds change the temperature display from Celsius to Fahrenheit.