There's marine motor oil, and then there's Bass Pro Shops 4-Stroke 10W-30 Premium Blend Marine Engine Oil. Our 4-stroke oil delivers a unique blend of highly refined mineral-based stocks, performance additives, rust and oxidation inhibitors, and lubricity enhancers. Cold-temperature protection makes this boat oil a superb all-season performer suitable for use under the most extreme conditions. Elite detergency additives keep engines running clear, helping to minimize deposits in the exhaust and combustion chamber, and helping to sustain peak performance. Always striving to give you more, we developed Bass Pro Shops 4-Stroke 10W-30 Premium Blend Marine Engine Oil with next-generation, viscosity-controlling additives to maintain a more uniform viscosity and protective film in the highest ambient temperatures, reducing wear and prolonging engine life. It's even safe to use on all major brands of high-horsepower outboard motors, stern drives, and personal watercraft that require NMMA FC-W catalyst-compatible quality oil. Improved lubricity Reduces engine deposits Viscosity-controlling additives Reduces corrosion and ring sticking Meets and exceeds NMMA and OEM requirements Safe for high-horsepower outboard motors, stern drives, and personal watercraft