All tubes are seamless and mold-cured (vulcanized) to ensure uniform roundness and improved reliability at the valve stem. Each and every tube passes a stringent 100% quality control inspection.Key Features:Butyl rubber Race inner tube.Seamless construction, with a mould-cured vulcanisation, to ensure uniform roundnessBy fitting different types of tubes you can actively influence the handling characteristics of your bike with little effort. Different wall thicknesses and the associated characteristics make this possible. All tube types listed are made of a high quality butyl mixture.