Welded oval center/center muffler, 2.25-inch or 2.50-inch free-flow straight-through center muffler, wrapped in stainless steel mesh. 6 inches x8 inches x14 inches, mainly influenced by the medium drum. However, in the refitting field, high-speed performance is generally emphasized, and the refitted parts will appropriately reduce the back pressure of the original factory, so the middle drum is usually shorter and thicker than the original parts. Street running and racing are not even equipped with drums.