Neighbor Haters are not for the faint of heartThese are an aggressive slip-on muffler, for those who think loud just isn't good enoughStart as round 4-inch tubes, then bell out to 4.5-inches, for an aggressive and classic design at the rearInternally, these mufflers have a spun and louvered baffle, but only for 8-inches This is done in order to produce an aggressive, barkAt the end of the baffle is a trumpet shaped inner tip that works in harmony with the belled end, creating a unique look