Michelin X Line Energy Z Ultra-fuel-efficient tire that delivers our longest mileage in line haul steer applications • Dual Compound Tread delivers more mileage without compromising ultrafuel-efficiency and retreadability • Directional tread with enhanced shoulder rib designed to deliver even wear to the end • 3-Retread Limited Warranty Approved for use on EPA SmartWay® certified equipment and meets California CARB requirements. Tread Depth - 19/32"