The Continental MTB Inner Tube has been made seamless and mold-cured (vulcanized) for reliable roundness at the valve stem - a great inner tube for mountain bikes.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 effortDifferent wall thicknesses and the associated characteristics make this possibleAll tube types listed are made of a high quality butyl mixturePresta or Schrader valve---