Challenge's Grifo 33 Tubular excels in snow, mud, grass and firm dirt thanks to a tread with excellent pedaling, cornering and braking traction. The Grifo also has a puncture-resistant layer beneath the tread. And it's built on their light and supple 260tpi hand-made SuperPoly casing with polyester-reinforced sidewalls for excellent durability. You also get a latex tube. Latex tubes are lighter, thinner and more flexible than butyl tubes, increasing your comfort, lowering rolling resistance, and helping to prevent flats, too.