Compared to the traditional casing, we have reduced the number of components and weight of our spun converters, which in recent years have been widely used as lightweight cases for catalysts, and also as mufflers. By using a structure that retains the entire catalyst surface mat support, the mat functions as an insulating material. In addition, it is filled with glass wool which functions as the sound absorbing element. This reduces the surface temperature of the casing, and allows it to be used without the need for an insulator. We use the thinnest gauge of 1.0 mm.