Box Schwalbe inner tube Workshop 28 Inch Dutch - DV17 28/47-622/635. The Schwalbe inner tubes are reliable. Bicycle retailers appreciate it for its high reliability. Each tire is inflated at the factory and tested for airtightness for 24 hours. The tire retains air pressure for longer. In production, Schwalbe requires a very high butyl content and very high material cleanliness. For example, the Schwalbe inner tube retains air pressure significantly longer than other inner tubes. It is a group inner tube system: A Schwalbe inner tube is extremely elastic and fits several tire sizes. This is why they are called groups of inner tubes. For example, the inner tube with number 19A fits tire sizes from 27.5 inches to 29 inches and widths from 40 to 62 mm. Finally, the tire is 100% fully recyclable. Standard version: High reliability, proven for many years.