Our Cobb Premium Bicycle Tubes are made of thin high-grade butyl rubber to resist pinch flats and leak downs while offering high performance. We offer two diameters and four presta valve lengths to accommodate a wide range of tire widths and rim depths. The presta valve is threaded externally, so use the included nut to prevent that annoying valve rattle in your rim. Grab a few extra for friends or make a friend out on the road because you’re prepared.