Hand TIG-welded stainless steel construction1-3/4'' headpipes step up to 1-7/8'' into the collector to increase flow and improve performance 4'' diameter straight can 11'' muffler body includes matching aluminum end capRemovable spiral-core louvered baffle features an aggressive sound18 mm and 12 mm O2 ports with adapters and plugsPartial heat shields and mounting hardware includedMade in the U.S.A.