High quality blend just for your outboard. Marine engines operate in a completely different environment from automotive engines. For this reason Sierra formulated this synthetic blended oil to provide corrosion protection to internal engine parts. A premium grade synthetic oil and mineral based oil are combined with additives to reduce wear and minimize deposits and make this an easy choice for boaters and mechanics. Engineered to meet or exceed engine manufacturer specifications. Key Features Formulated specifically for marine outboard engines Blend of premium grade synthetic and mineral based oils Provides corrosion protection Reduces wear on internal engine parts Reduces piston ring depositsNMMA FC-W Certified/API-SL