Specialized isn't afraid to say that their GRIPTON Compound is the best out there. And when combined with an ultra-supple 320 TPI cotton casing, you get a tire that's very special. You get the Turbo Cotton tire. Both materials stand for master craftsmanship, and they work in harmony to reflect our dedication to building the world's fastest tires. By bringing both of these materials together, they've created the best clincher tire out there. It provides a clear-cut performance advantage.