Cast iron ball valves offer a considerable cost advantage and have a wide range of permissible service applications in practically every field of industry. They are commonly used on water, steam, oil, and gas services and find numerous applications in the handling of chemicals, dyestuffs, paints, textiles, and many other industrial products where a degree of iron contamination is of little or no consequence. The operating temperature range for cast iron ball valves is usually from ambient up to around 220 °C. Valves are also available in s.g. (spheroidal graphite) iron (also known as nodular or ductile iron), a form of cast iron in which the graphite is present substantially in nodular or spheroidal form instead of in flakes as in grey iron. This modification to the structure of the metal gives it mechanical properties superior to those of ordinary grey iron without detriment to its other characteristics. Consequently, valves made of s.g. iron can be used for operating pressures higher than those associated with grey iron valves.