Auto and General Castings Pvt. Ltd. Manufactures Parallel Threads Valves. Auto and General Castings Pvt. Ltd. Is an ISO 9002 certified company. Parallel Threads 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 Parallel Threads Valves are available in variable sizes and variable operating pressure.