Quicksilver Full Synthetic 4-stroke Marine Engine Oil 8M0175781 is for use in non-catalyzed 4-stroke outboard, sterndrive and inboard engines. This is a one gallon bottle. Quicksilver 10W-30 Full Synthetic 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. The Quicksilver brand is the leader in delivering uncompromising engine oils, parts and accessories to the marine industry for over 65 years. Quicksilver is the premier supplier of Mercury Marine Original Equipment replacement engine parts, oils, and accessories, but also works to serve all Original Equipment brands in the marine and powersports industries. It has earned a loyal following by providing the highest quality products that are tested through some of the most rigorous environments and testing procedures. No aftermarket company comes close to the level of research and design as Quicksilver; buying Quicksilver is buying performance, protection and peace of mind.