Collectors with expanded diameter that merge into an original megaphone silencer with an inverted cone style. To achieve greater exhaust gas flow and therefore greater performance, the diameter of the header pipe increases from 1-3/4" to 1-7/8" in the collector 4” muffler body with billet end cap Baffle with "NACA" type air intakes (removable) is included. Mounting hardware included 12" silencer Heat protectors are included. Made in the U.S.A.