Features: Special vertical screw design, heat the water more quickly and evenly. Professional Aquarium Heater: Keep the water temperature steady and helps to avoid disease and death of fish. Automatic Temperature Adjustment: Easy operation and highly efficient, saves you from large electricity bills. 100% Waterproof Explosion-proof: Perfect for 2-15 gallon tank. It would be better buy two and use together if there is a bigger tank. Safe for Use: Equipped with an integrated thermal protection circuitry to prevent any overheating or electric shock. With 2 Strong Suction Cups: Ideally place it where you can access the red knob for temperature control. It can be installed both horizontally or vertically.