Using advanced gas dynamics and sophisticated noise cancellation acoustics, Moroso engineers have developed these Spiral Flow stainless steel racing mufflers. The specially engineered spiral baffles that are wrapped around a "straight-through" core divide the exhaust flow into two separate paths. This significantly reduces noise levels with minimal effect on the backpressure. They have a round tube case with centered inlets and outlets, and feature polished stainless steel construction for the ultimate in durability.