Manufactured with a thermoplastic elastomer, called TPU. These tubes are lighter, and more robust than traditional butyl rubber inner tubes At a featherweight 23g the super-compact (when rolled up) S-Tubo Road stands out with very low rolling resistance which outpaces standard rubber tubes yet is comparable to latex tubes With 78% smaller packed size and the same puncture resistance as standard tubes the S-Tubo Road is the perfect choice as a spare and can be the crucial factor when you&&';;re riding long and hard Specifically made for disc brakes (not suitable for rim brakes) Labeled Size: 700 x 18-28 Shaft Type: Smooth Tube Compound: Thermoplastic Elastomer ISO Diameter: 622 / Road / 700c Valve: Presta - choose; 42mm, 60mm, or 80mm Weight: 23g.