The Schwalbe No. 7A inner tube fits 20" tyres with a width of 28-37 mm and is used for children's bikes, unicycles, trailers, folding bikes and BMX bikes, among others. Schwalbe tubes have proven themselves on the market for years thanks to their excellent manufacturing. They are uniform in wall thickness and round in running. Their precise seams make them durable. A comparative test showed that the Schwalbe inner tube keeps the air pressure stable for significantly longer than other tubes, which lost almost twice as much air pressure in 30 days. One possible reason for this could be a lower butyl content in the other tubes. The special quality of Schwalbe inner tubes results from the uniqueness of their rubber compound. To guarantee this high quality, every single Schwalbe inner tube is inflated and checked for at least 24 hours before it leaves the factory.