Quicksilver 10W-30 4-Stroke Full Synthetic Marine Engine Oil Quart. For use in non-catalyzed 4-stroke outboard, sterndrive and inboard engines. Features a specialized additive package with elements that protect hard-working marine engines. It protects internal engine surfaces from deposit buildup, neutralizes harmful byproducts of fuel combustion and provides industry-leading defense against rust during intermittent engine use. It exceeds NMMA® FC-W® standards for non-catalyzed outboard, sterndrive and inboard engines.