Specifically formulated and developed to meet the needs of all 4-stroke outboard engines and for the rigors of the marine environment. This is an industry leading corrosion protection that features a premium-grade synthetic and mineral-based stocks with specially designed marine grade additives not required in automotive oil. This has been rigorously tested to guarantee warranty protection for Mercury and Mariner 4-Stroke outboards. It contains outstanding lubricity for internal engine components to reduce wear, scuffing and scoring. Lastly, it has excellent running quality and long-term reliability.