Finnex 100-Watt Hang-On Digital Controller Aquarium Heater, Titanium Tube, 20 to 30-Gallon

Maintains Water Temperature within +/-2º F of the setting value. Memory Chip to restore previous settings. Corrosion-resistant, fast heating titanium tube. Precise electronic control with transparent design. Finnex used new technology to create a precision digital control that maintains water temperatures at a constant level. In case of a power failure, heaters are equipped with memory to bring you tank back to it's original settings without any unfortunate mishaps upon power return.