Looking for a tire that's more aggressive than the mixte-tread GravelKing? The GravelKing SK might just be the tire you need for the more hardcore roads. Aggressive knobs, ZSG Natural rubber compound, puncture protection breaker and AX-α special low rolling resistance casing make the Gravelking a go-anywhere tire. And tubeless compatible up to 60 PSI! The Gravel King SK + model has side reinforcement with Protite and bead-to-bead nylon puncture belt, resulting in a 4ply, super tough casing. FEATURES: ZSG Natural Compound: This compound has the same low rolling resistance as the premium compound. Its enhanced wear resistance makes it perfect for a long lasting training tire with an excellent ride. Advanced Extra Alpha Cord: AX technology uses extremely narrow cord which is weaved at a super high density into the casing for lightness and flexibility. This increased density improves resistance to cuts and abrasions. Anti-Flat Casing: Anti-puncture reinforcement throughout the tire strengthens resistance to cuts and pinch flats. Made in Japan