The knurled center tread transitions to a file tread along the edges for confidence in the corners The knurled center tread transitions to a file tread along the edges for confidence in the corners Light, fast-rolling, high volume slick for gravel or do-it-all road bike DC - Dual Compound tread provides a lower rolling resistance center paired with extra grip for the corners SS - SilkShield offers bead to bead puncture protection covering the tread as well as the sidewalls TR - Tubeless Ready - sealant required