Features: 1SAFE AND EFFICIENT: Aquarium heater with silicon carbide heat conduction, faster and more stable heating, can guard fish and users from scalding. PID temperature control algorithm to achieve high thermal energy, low power consumption. 2CONSTANT TEMPERATURE: This fish tank heater uses intelligent frequency conversion technology, the power size is freely adjustable by the chip, soft temperature control, always maintain a minimum power constant temperature. 3WITH CONTROLLER: The fish tank heating rod has an external controller and is equipped with the most advanced heating chip to precisely control the fish tank temperature. High purity nitinol wire, thickened heat transfer, faster heating and power saving. 4TEMPERATURE ADJUSTMENT: Submersible aquarium heater has an ultra short rod body, only 23cm/9.1in long, external controller display in Fahrenheit for easy viewing, turn the knob to adjust the temperature, more intuitive. 5PREMIUM MATERIAL: Aquarium heating rod has a sturdy housing made of high temperature resistant ABS material, with explosion proof quartz tube and high temperature resistant nickel chromium heating wire inside. Package included: 1 x Aquarium&nbspHeater 2 x Suction Cup 1 x Instruction&nbspManual