Continental bicycle tubes are constructed of durable, seamless butyl rubber and are 100% inspected to ensure high quality and reliability. Seamless, and vulcanized to ensure uniform roundness and improved reliability at the valve stem. Every tube passes a stringent 100% quality control inspection. Continentals Uni-tube system allows greater compatibility with more tire sizes and fewer tubes. All Continental Tubes are seamless and mold-cured to ensure uniform roundness and better reliability at the valve stem. Features: UNI-TUBE - Continentals Uni-tube system allows greater compatibility with more tire sizes and fewer tubes. VULCANIZED TUBES - All Continental Tubes are seamless and mold cured to ensure uniform roundness and better reliability at the valve stem. Comes in at a feathery 110 Grams Fully Vulcanized, Seamless and Mold Cured The removable valve core makes adding Revo Sealant quick and easy Lightweight tubes have a lower thickness and so it is imperative that inflation pressures are maintained to prevent the risk of pinch flats.