Feature: 1. ULTRA SHORT BAR BODY: Submersible fish tank heater is made of high temperature resistant ABS material with ultra short bar and external knob to adjust temperature for more intuitive control. 2. HEATS UP FASTER: Submersible aquarium heater with explosion proof quartz tube and high purity nitinol wire inside, thickened heat transfer, faster and more stable heating. 3. PID TEMPERATURE CONTROL ALGORITHM: Preserve fish, aquatic life and users from scalding. PID temperature control algorithm realizes high heat energy and low power consumption. 4. INTELLIGENT INVERTER TECHNOLOGY: Using intelligent frequency conversion technology, the power level is freely adjusted by the chip, always maintaining the lowest power constant temperature. 5. EXTERNAL CONTROLLER: Adjustable aquarium heater has an external controller and is equipped with the most advanced heating chip to precisely control the temperature of the aquarium. Specification: Item Type: Submersible Fish Tank Heater Material: ABS Use: Aquarium Automatic Thermostat Heater Plug Specifications, Voltage: EU Plug, 220V Temperature Control Range: 16-34℃ Length: Approx. 23cm / 9.1in. Package List: 1 x Submersible Fish Tank Heater2 x Suction Cup1 x Instruction Book Note: Manual measurement, please allow slight error