A. O. A. O. Smith's 40-gallon model is designed to last. It features dual copper heating elements, a protective anode rod and a ceramic fused tank shield designed to reduce corrosion and provide ultimate tank protection. It also features a self-cleaning dip tube designed to reduce sediment build-up and extend the overall life of the water heater. Want to save money on your energy bills? This model operates at a 0.88 Uniform Energy Factor (UEF) which can reduce your energy consumption compared to less efficient models. Not sure if this is the right water heater for you?