SmarTUBE X: Maximum robustness and puncture resistance for an urban gravel or e-bike use. The Pirelli SmarTUBE inner tube family is made of thermoplastic polyurethane TPU that is a characterised by high elasticity and mechanical resistance and extreme lightness. Pirelli SmarTUBE X TPU inner tubes are designed for use with the Pirelli CINTURATO and ANGEL tyre families: three times thicker than the first generation CINTURATO SmarTUBE  the SmarTUBE X offers an increased level robustness and puncture resistance. It is particularly suitable in city settings or for fast commuting where their speed and reliability characteristics are highly valued. The SmarTUBE X tubes in line with Pirelli’s TPU inner tube family are extremely compact: -50% space taken up in a jersey’s pockets or in the backpack and up to 70% lighter compared to the traditional butyl inner tubes these TPU inner tubes make for an excellent space saving back up to carry on longer rides.  SmarTUBE X tubes come in a range of Presta and Schrader valves in a range of lengths to suit many different rim profiles. Intended for fast commuting or endurance oriented set up in combination with the Pirelli CINTURATO and ANGEL Tyres. Cinturato SmarTUBE X;- Presta valve: 42mm length to work with the majority or rim depths black colour for a clean and understated look;- Weight: 700 x 28.40c PV - 146g 700x40/50c PV - 150g;-Intended solely for Disc Brake equipped bikes DO NOT USE if bike is equipped with RIM Brakes.