Straight from the horse's mouth.
"Royal Purple® Motor Oil 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.
Environmentally Responsible: Royal Purple® Motor Oil extends oil drain intervals. Less oil is purchased and less oil is being disposed of—It's good for your vehicle, and good for the environment!"