Flex Dimensions ---------------Inlet Diameter 3" I.D. Outlet Diameter 3" I.D. Flex Length 6" Vibrant flexible couplings are engineered to isolate vibration generated by your vehicle's engine, thereby relieving stress on the exhaust system. Flex couplings reduce premature cracking of manifolds and downpipes and help extend the life of other components. TurboFlex couplings feature an internal stainless steel interlock liner that facilitates smooth flow of high temperature exhaust gases. These flex are recommended for high performance (especially forced induction) applications.