Bicycle inner tube for single-speed fixed gear bicycles, road bicycles, mountain bicycles, commuter bicycles, urban city bicycles, folding bicycles. Those fancy new tires you bought aren't worth much without a great set of inner tubes to keep them inflated. Put the Projekt 700c valve tubes in your deep profile rims to shed some grams and keep the air in your tires. Airtight system allows greater compatibility with more tires sizes seamless construction eliminates weak points. Mold-cured and vulcanized for uniform roundness and improved reliability at the valve stem insertion. Every tube must pass 100% quality control inspection. 48mm valve.