Features: 1POWER 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. 2SAFE 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. 3CAUTIONS: 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. 4ACCURATE TEMPERATURE CONTROL: The aquarium external heater features precise temperature control, small temperature differences and an over temperature protection system for greater safety. 5LED DISPLAY: The submersible aquarium external heater features an LED display for easy control, high end, precise waterproofing and an outstanding sealing effect. Package included: 1 x Aquarium External Heater&nbsp 4 x Hose Fitting Kit&nbsp 4 x Gasket&nbsp 2 x Hard Pipe Fitting 2 x Retaining Hoop&nbsp