Schwalbe SV 21A ExtraLight tube for 27.5 "For 27.5"/650B MTB bikes and tires from 1.5" to 2.4" wide.Suitable dimensions40-584 27.5 x 1.5047-584 27.5 x 1.7550-584 27.5 x 2.0054-584 27.5 x 2.1057-584 27.5 x 2.2560-584 27.5x2.3562-584 27.5 x 2.40Weight: 150gStability of air pressure: Schwalbe hose keeps air much longer. The quality of the ingredients and the purity of the rubber compound determine the quality of the hose when it comes to the material. During vulcanization, each Schwalbe tube is placed in a mold and inflated. This is the only way to ensure uniform wall thickness and excellent air retention.Reliability:Constant inspection to ensure the highest possible operational reliability: Each hose is inflated at the factory and stored under pressure for 32 hours to check the air content.Group tube system: Due to its high flexibility and quality, a single inner tube covers a wide range of tire sizes. For example, hose No. 17 at 28 mm tire width as well as at 47 mm. Only an extremely high-quality and reliable hose can meet this requirement.VERY GOOD The only hose with a rating of "very good" from the Swiss consumer magazine Kassenrutsch. May 29, 2012. in a test of 12 hoses. Test winner: Schwalbe SV13Longer holds air!A selection of tubes from tire brands, private labels and "no name" products were included in the comparison test. The result was clear. The other inner tubes lose almost twice as much air pressure as the Schwalbe tube on average in 30 days. Possible reasons: lower butyl content, lower butyl quality. Schwalbe is uncompromising in its demands here.Different inner tubes on the same rim and the same tire. Tire size 47-622.Start at 5 bars. Loss after 30 days.