A tube is not just a tube. Airtight. In addition to the quality of the ingredients, the purity of the rubber mixture is crucial to the quality of the tube. The base material is therefore sieved at high pressure through seven filters before being extruded. All tubes are inserted into a mold and inflated for vulcanization to ensure consistent wall thickness and high air pressure. Reliability. All tubes are inflated and stored for 24 hours to test air pressure retention. Each tube is subjected to careful visual inspection. This special quality control helps to avoid unpleasant surprises and that is why for many years Schwalbe inner tubes have become highly respected for their exceptional reliability. Group tube system. Only high elasticity and good quality allow a tube to cover many sizes of tyres. Tube No.17 can fit tire width between 28mm and 47mm, which is a great advantage in the trade and at the same time it guarantees the quality of the tube. Only high-quality and reliable tube meets this requirement. alve All valves are nickel-plated and threaded and the valve inserts are replaceable. Schwalbe inner tubes with the classic bicycle valve are also able to test pressure thanks to a high-pressure valve seal. And it's simple to see each tube is crowned with a clear polycarbonate dust plug.