Sierra International 18-2833-9 Exhaust Elbow Gasket - Pack of 2 Sierra Exhaust Elbow Gasket Meets or exceeds the original equipment quality Sierra part number: 18-2833-9 Interchangeable with the following: Barr MC472799777, GLM 31520, Mallory 9-61407, Mercruiser 27-997772, 27-997771, 27-99777, 27-52076, 27-99777B2, Osco 52076