A. O. Smith Corporation is a manufacturer of water heating equipment, serving a diverse mix of residential and commercial end markets principally in the United States. The Company operates in two segments: North America and Rest of World. Both segments manufacture and market comprehensive lines of residential gas, gas tankless, oil and electric water heaters and commercial water heating equipment. The North America segment also manufactures and markets specialty commercial water heating equipment, condensing and non-condensing boilers and water systems tanks. The Rest of World segment also manufactures and markets water treatment products, primarily for Asia.