A.O. Smith Corporation is an American manufacturer of both residential and commercial water heaters and boilers. It is the largest manufacturer and marketer of water heaters in North America. It also supplies water treatment products in the Asian market. The company has two operating segments: North America and Rest of World. The North America segment manufactures and markets a comprehensive line of residential and commercial gas, gas tankless, electric and solar water heaters, as well as boilers. The Rest of World segment manufactures and markets specialty commercial water heating equipment, condensing and non-condensing boilers, and water systems tanks.