SENGAIKI 4T 5W-30 API SN is our best full synthetic Outboard oil FC-W® rated by the National Marine Manufacturers Association (NMMA®). Contains all the benefits of SENGAIKI 4T, with increased lubricity for lower friction levels resulting in potentially improved fuel economy. Recommended primarily for all types of outboards engine. Also works well in other all types of inboard engines. 5W-30 weight provides excellent lubrication in all climates.