Feature: 1. POWER FAILURE MEMORY: The aquarium external heater automatically resumes its previous settings after a power failure, eliminating the need to reset the temperature and avoiding forgetting to adjust it after a power failure. 2. SAFE AND RELIABLE: The aquarium external heater is designed with a water circuit for heating and the water and electricity are separated to prevent the danger of leakage. 3. CAUTIONS: The aquarium external heater shows an E3 relay key bonding fault, which cannot be recovered even after troubleshooting and must be pressed for more than 2 seconds before the fault can be removed. 4. ACCURATE TEMPERATURE CONTROL: The aquarium external heater features precise temperature control, small temperature differences and an over temperature protection system for greater safety. 5. LED DISPLAY: The submersible aquarium external heater features an LED display for easy control, high end, precise waterproofing and an outstanding sealing effect. Specification: Item Type: Aquarium External Heater Material: Plastic Size: Approx. 8x73x185mm / 0.31x2.87x7.28in Fitting Tube Diameter: Hose: 18mm/0.71in, 22mm/0.87in Hard Pipe: 25mm/0.98in Use: Fish Tank External Heater Control Range: 20℃-34℃ Suitable for Water Capacity: Below 200L . Package List: 1 x Aquarium External Heater 4 x Hose Fitting Kit 4 x Gasket 2 x Hard Pipe Fitting2 x Retaining Hoop Note: Please allow for some errors in manual measurements.