Quicksilver 10W-40 Four Stroke Mineral Base Oil. SAE 10W-40 weight. Formulated with a special marine additive package. Provides outstanding wear and corrosion protection to help extend engine life. Recommended for use in all four-stroke marine outboard, stern drive and inboard engines. Eliminates thermal breakdown under extreme RPM. Meets or exceeds all marine engine manufacturer's warranty requirements and recommendations for use of an FC-W marine engine oil. It maintains its viscosity, protects against varnish buildup and sludge formation and exceeds the rust protection requirements for NMMA certification. Quart.