This is the Exhaust Gasket for the O.S. Engines GT55 Gasoline Airplane Engine (OSMG1555). FEATURES: Fiberous material Grey in color INCLUDES: One exhaust gasket REQUIRES: Installation between muffler and crankcase SPECS: Length: 51mm (2.01") Width: 24mm (.94") Thickness: .8mm (.31") lmm 04.13.10 ir/jxs