The Extreme Duro Protex is one tough tire. ZSG Ultima compound, 3D casing and 400D cord make the casing almost impenetrable. If you train or race on rough roads, this is the tire for you. Unique 3ply overlapping casing design strengthens the tire from sidewall to sidewall Nextgeneration Zero Slip Grip compound is grippy and long lasting ZSG Zero Slip Grip Dual Compound tread is stickier on the sides for cornering and harder in the center for less rolling resistance Protex shie