This is the Replacment Exhaust Stack (manifold) for the Swing Muffler. / This is for the following SuperTigre Engines: S-40, S-45, GS40, GS45, & G51 / / FEATURES: Aluminum Construction / / INCLUDES: One Exhaust Stack / One Exhaust Gasket / Two 3x17mm Screws / Two 3mm lock Washers / / SPECS: Outside diameter of round port: 20mm / Length of exhaust stack: 53mm / 6-1-94 KrH / ir/jl