A catalytic converter is part of a car's exhaust system. Catalytic conversion device is an exhaust purification device that converts CO, HC, and NOx in exhaust gas into gases that are harmless to human body by using the action of catalyst, also known as catalytic conversion device. The catalytic conversion device converts the three harmful gases CO, HC, and NOx in the exhaust gas into harmless gases carbon dioxide, nitrogen, Hydrogen and water. http://www.xichuangcatalyst.com/catalytic-converter/