Mueller Co. has a long history of trust and leadership in the American flow control industry spanning more than a Century. Mueller Co. is the largest full-line supplier of flow control products used in distribution systems for municipal potable water and natural gas, and is ISO certified. The Hersey Meters Division of Mueller Co., with an equally long history of acceptance and also ISO certified, manufactures water meters, automatic meter reading (AMR) systems, and backflow prevention devices used by the water distribution, fire sprinkler, plumbing and industrial process industries. Mueller's Henry Pratt Valve Subsidiary is the largest supplier of valves for the water distribution, water treatment, nuclear, fire protection, and power generation markets. Pratt® valves are installed in water treatment plants, water distribution systems, power plants and industrial facilities worldwide.