Mercury 25W-40 Marine Engine Oil features high-tech, advanced anti-wear additives that provide up to 35% better camshaft wear protection. Additionally, this formula offers the highest levels of corrosion and oxidation protection. Designed to maintain engine reliability and performance, tests have shown that Mercury 25W-40 Marine Engine Oil holds its viscosity ratings longer in industry wear-testing than other oils on the market. Mercury Oil, combined with a Mercury Oil Filter will offer optimum marine engine protection.