• 25W submersible heater designed for freshwater aquariums from 3 to 19 liters • Made with high-quality materials: nickel-chromium heating wire and explosion-proof insulated quartz tube, with an external ABS housing resistant to high temperatures • Dual safety protection system via chip, safe for fish and users • Digital controller that displays real-time water temperature and operating status • Adjustable temperature range between 15 and 34°C, with ±1°C accuracy • Automatic shut-off if the temperature exceeds 35°C or if the heater is exposed to air, displaying warning codes on the controller • Memory function that retains previous settings after restart • Allows switching between Celsius and Fahrenheit units by holding the button for 3 seconds • Removable protective cover for easy cleaning and to prevent small fish from getting stuck • Compact design and 1.6-meter power cord for greater convenience during installation • Must be fully submerged in water during operation • It is recommended to cut the power and let the heater cool before cleaning or changing the water • Can be installed alongside a pump or filter to improve water circulation and prevent local overheating