Stepped headers merge into a true reverse-cone megaphone muffler. 1-3/4″ headpipe steps up to 1-7/8″ into the collector to increase flow and improve performance. 4″ muffler body with billet end cap. Removable spiral-core louvered baffle included. includes mounting hardware. Includes O2 sensor port plugs. Heat shields included. Made in the U.S.A..