Cobra Powr-Flo Slip-On Mufflers - Chrome - '95-'16 FL135365613 Product Description 4 1 2" body tapers to 4" round at the front 4 1 2" machined aluminum, thin line tip 3" cores for superior performance Acoustical engineering developments allow an incredibly deep sound because of intense, class leading resonance absorption and prevention Uses proprietary materials with specific acoustical dampening and thermal insulation properties The frequency and location of the perforation patterns in the cores