Quicksilver 4-Stroke Synthetic Blend 25W-40 Marine Engine Oil - The Quicksilver 4-Stroke Synthetic Blend 25W-40 Marine Engine Oil outperforms automotive oils in marine applications because of its specialized additive package designed for marine engines. Features: For use in all 4-Stroke marine engines – New formula 4-Stroke oils are engineering approved for all marine 4-Stroke applications, including: Outboard, Mercruiser, High Performance, Stern Drive/Inboard, and exceeds all marine industry 4-Stroke oil requirements including FC-W and FC-W Catalyst Compatible. Flagship engine and corrosion protection – Industry leading strength and viscocity retention and ultimate corrosion and wear protection . The most recommended marine oil – Over 5 years of engineering and decelopment by the largest marine engine manufacture in the world. 25W40 Synthetic Blend recommended in all Marine Engines