Michelin g4 airstop butyl 20 tubethe airstop butyl range of tubes fulfills the needs of everyday cyclists for an economical high quality tube it features good puncture resistance and an excellent pricequality ratio thats backed up by the impeccable reputation of michelin please note metric and imperial measurements are listed on the box this is suitable for a 20 wheel bike buymichelin wheels tyresfrom chain reaction cycles the worlds largest online bike store