Copper covered fiber Exhaust Port Gasket produces a leak proof seal when the exhaust pipe does not fit square with the port. High temperature flexible fiber center and the soft copper cover conforms to exhaust port to eliminate leaks. Gaskets can be stacked one on top of the other for extreme exhaust leaks. Fits Big Twin Evolution 1984/Later, Twin Cam 88 1999/Later, and Sportster Evolution 1986/Later