The Jobe Valves Megaflow Valve is a float-operated valve for use in automatic filling of water troughs. The float-operated valve is configured for underwater mounting only. The float is connected to the valve with a nylon cord, which operates a pilot valve. When the water level drops, the pilot valve is opened and the main diaphragm valve is activated. A Megaflow valve is a good choice where its high-flow, compact, robust, non-corrosive construction is beneficial.