2.50-inch or 3.0-inch free-flowing straight-through core is wrapped in stainless steel mesh. Some circular welded silencers can also see double output, but this is different from large cars. Most of the large cars are two pipes or a thick pipe, which leads to two small mufflers and then to the double tailpipes. Moreover, the small-displacement vehicle is a single tube, and it is relatively thin, which leads to a large muffler package and then is divided into two tailpipes, which is more decorative. Of course, there are also special ones, such as old Mitsubishi EVO's unilateral unilateral unilateral, old Subaru STI's unilateral unilateral, old GTR's unilateral unilateral, and Megane RS's middle unilateral unilateral. However, their tail pipes are thick enough, and the muffler package is relatively small, so it will not affect the exhaust gas circulation. After all, they are mainly performance.