The Criterium Tubular is the most versatile and winning tubular in Challenge's line. It's hand made on a light and supple 320tpi CoreSpun woven-cotton casing with a long-wearing tread compound. The center tread rolls quickly while the side tread sticks to the road in the corners. There's also puncture protection under the tread. Plus, you 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.