Downpipe designed for: BMW F10 BMW F11 BMW F18 Downpipe by TurboWorks, is made of 100% stainless steel. Inlet diameter: 86 mm Outlet diameter: 61 mm The downpipe for: BMW F10 BMW F11 BMW F18 The downpipe by TurboWorks is made of 100% stainless steel. Inlet Diameter: Outlet Diameter: