Auto and General Castings Pvt. Ltd. Offers Self Closing Valves. Auto and General Castings Pvt. Ltd. Is an ISO 9002 certified company. Self Closing Valves mainly deal in gas or LPG products or equipments. The raw materials used in manufacturing of these gas valves are brass and steel, which are completely corrosion-resistant. The Self Closing Valves are available in variable sizes and variable operating pressure.