Sierra International 18-5139 Marine Contact Set for Mercury/Mariner Outboard Motor Sierra Contact Set Meets or exceeds the original equipment quality Sierra part number: 18-5139 Interchangeable with the following: Mercury 336-4318A2, 336-3948A3, 336-4318A3, 336-4318A, 336-3948A2 Fit specific, check part numbers to ensure proper fit