This product is Continental ULTRA SPORT 3 folding brown tyre/black tyre, suitable for bikes with wheel diameter 70028C in folding box (one tyre per box). Model: Ultra Sport IIl. Tread: PURE GRIP compound. PURE GRIP compound Introduction. This technology is based on an active silica compound, which has been developed through in-depth laboratory research. This compound provides better grip and durability than its predecessor, making it safer for the rider.