These have the classic megaphone shape capped with a large machined aluminum tip that has the Cobra logo engraved on top. Delivers a deep sonic thump that keeps that powerful V-Twin rhythm going for miles and miles. Internally, the spun-louvered core provides the bark and horsepower increase you expect from Cobra. Muffler starts as a 2-3/4″ piece of tube, and morphs into 4″ at the rear. When this muffler is used with the Cobra head pipe it requires the use of an optional tapered heat shield. This heat shield is not required with the stock M8 head pipe..