Gravel, dirt or rough pavement. The most durble version of the “GravelKing SK” series. Features ZSG (Zero Slip Grip) Natural Compound AX-a Advanced Extra Alpha Cord ProTite Shield + Plus Sizes: 700 x 26c / 700 x 28c Weight: 260g / 300g Colours: Black/Black, Black/Brown Made in Japan Technologies AX-a Advanced Extra Alpha Cord ProTite Shield + Plus ZSG (Zero Slip Grip) Natural Compound This compound has the same low rolling resistance as the Ultima compound. Its enhanced wear resistance makes it perfect for a long-lasting training tyre with an excellent ride.