Royal Purple Motor Oil is recommended for use in all four-cycle gasoline engines and both two-cycle and four-cycle diesel applications including automotive, commercial fleet, and stationary industrial diesel engines. Royal Purple is a tough, long life, high performance oil that delivers superior protection and enhanced performance to gasoline and diesel engines. It gains its performance advantages from a blend of synthetic oils plus Royal Purple's proprietary, synthetic Synerlec additive technology. Synerlec additive technology greatly reduces engine wear, including ring, cylinder, and bearing wear. It is extremely tenacious, adheres to engine surfaces and remains after shutdown, which provides protection upon initial startup. Decide which oil is right for you. Royal Purple Motor Oil is available in specially formulated multi-viscosity and straight grades for use in gasoline and diesel engines of all types from cars and trucks to SUV's and boats. Royal Purple Motor Oil with Synerlec lowers operating temperatures, provides superior corrosion protection, improves fuel econonmy, reduces emissions, extends oil life, and reduces friction, which results in a 1 to 3 percent increase in horsepower. A.I.P. Certified. Available Oils Multi-Grade Oils: 5W20, 5W30, 10W30, 10W40, 15W40, 20W50. Straight-Grade Oils: SAE 30, SAE 40, SAE 50