520ERVT breaks down the concept of the original motocross chain (non o-ring) and adds the benefits of an x-ring, X-Ring helps keep your chain sealed with lubrication, limits dirt and mud from getting in-between the side plates, and only has 4 contact points with the plates which means less friction than the traditional O-Ring chain, More lightweight and longer chain life, By adjusting the materials, the 520ERVT is now 2% lighter and has a 15% longer lifespan, all while maintaining the tensile strength