About this item Super Mini Size, 25Watt for 1-5 Gallons YukiHalu 25W aquarium heater is designed for 1-5 gallons mini fish tank. Compact design, take less space in the fish tank, easy to hide in the tank. Temperature can be accurately adjusted from 64 to 93°F. This heater suitable for both saltwater and freshwater. The rated voltage is 100-130V. Automatic Constant Temperature with 1℉Accuracy Thanks to advanced Intelligent Frequency Conversion Technology, the water temperature can be kept constant with an accuracy of 1℉. The heater’s working frequency will be changed according to temperature variation, and the heating is automatically stopped when the set temperature is reached. Compare to traditional heater, this new technology will cut down 49% electricity bill for you. Overheating Protection, Out of Water Protection The power will be cut off and stop heating automatically if the heater out of water or overheating. Protect your fish. Never cook your fish. External Temperature Controller, Never Wet Your Hands Use an external controller to set the temperature instead of immersing your hands in water to rotate the dial. Never wet your hands or contaminating your tank. Strong suction cups, easy to install. Built-in Temperature Sensor, Power-off Memory Function Dual built-in temperature sensor, the water temperature will be displayed on the external temperature controller in real time. No need to buy other aquarium temperature meter. The heater will remember the temperature setting, no need to reset the temperature after power off. Daily maintenance The suction cups must be cleaned every month to prevent the heater from falling off and breaking because the suction force is weakened by stains. Check before installation Check the glass tube first before installation, if the glass tube is cracked (not completely broken), do not use it