Stepped headers merge into a 3-1/2" short straight muffler body with Hot Rod turnout end cap 1-3/4" headpipe steps up to 1-7/8" into the collector to increase flow and improve performance Removable spiral-core louvered baffle included Hand MIG welding 18 mm and 12 mm O2 ports with adapters and plugs Includes mounting hardware Full heat shields included Made in the U.S.A.. EXH 2:1 B MD/HTROD FL 17+