This is a genuine OEM Mercury Marine Direct Fuel Injection (DFI) 2-Cycle Engine Oil designed for use in OptiMax and other DFI two-stroke outboard engines. It is formulated to meet the demanding lubrication needs of high-performance marine engines Advanced Lubrication - Specially formulated to reduce carbon buildup, smoke, and deposits in DFI 2-stroke engines OptiMax Approved - Recommended for Mercury OptiMax and other DFI outboards High Detergency - Keeps pistons and cylinders clean, extending engine life. Cold Weather Performance - Flows easily in cold conditions to ensure immediate protection at start-up OEM Quality - Factory-tested for compatibility and performance with Mercury engines.