Valves are control components in fluid delivery systems, with functions such as shutoff, regulation, diversion, backflow prevention, pressure stabilization, diversion or overflow pressure relief. Valves used in fluid control systems come in a wide variety of varieties and specifications, from the simplest shutoff valves to the various valves used in extremely complex automatic control systems. Valves can be used to control the flow of various types of fluids such as air, water, steam, various corrosive media, mud, oil, liquid metal and radioactive media.