Quicksilver Optimax DFI 2-Stroke Marine Oil High-performance Quicksilver Optimax Oil provides superior protection for all 2-stroke applications, including household brands like Mercury Optimax, Mariner Optimax, and other manufacturers direct fuel injected DFI 2-stroke outboards. With this oil, you can completely maximize the performance of Mercury, Mariner OptiMax, and DFI engines where reduced oiling rates and higher operating temperatures put increased demands on lubricants. By using Quicksilv