Beyond synthetic! Royal Purple's Max-Gear is an ultra-tough, high-performance, GL-5 automotive gear oil designed to provide maximum protection to heavily loaded gears, while maximizing power throughout the drivetrain. It outperforms many other oils because it combines the highest quality synthetic oils with Royal Purple's proprietary Synslide additive technology. Max-Gear makes your gears run smoother, quieter, cooler, and longer without overhauls.