Continental 42mm Presta Valve Tube, Black, 650 x 18-25cc PREMIUM INNER TUBES - Preferred by champions and riders worldwide VULCANIZED TUBES- All Continental Tubes are seamless and mold cured to ensure uniform roundness and better reliability at the valve stem. QUALITY TESTED- Every Continental Tube passes a stringent 100% quality control inspection. UNITUBE- Continentals Unitube system allows greater compatibility with more tire sizes and less tubes. REMOVABLE VALVE CORES - Useful for adding extenders or using Revo Sealant.