Designed specifically to address the needs of tuned motors built for high horsepower applications Use a unique extended inner collector maximizing performance 4" straight-style performance muffler body with 2-1/2" x 16-1/2" baffle and black billet end cap with contrasting machined flutes Oxygen sensor port plugs also included for non-sensor applications Made in the U.S.A.. EXHST 2-1 B1 91-11DYNA CH