For maximum speed, Challenge's Triathlon Tubular is light, fast and aero. It's hand made on their light and supple 320tpi SuperPoly casing with a durable tread compound and tough polyester in the sidewalls. The tread rolls fast, grips great in the corners and has a layer beneath for puncture protection. 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.