All InnerTubeShop inner tubes are sourced from experienced manufacturers that supply some of the best known premium tyre and cycling brands. We cut out the middlemen to bring you the same product and save your hard earned cash. These innertubes are compatible with the following ETRTO tire sizes: Metric Sizes 700 x 18 = ETRTO 18-622 700 x 21 = ETRTO 21-622 700 x 23 = ETRTO 23-622 700 x 25 = ETRTO 25-622 Imperial Sizes 28 x 3/4" = ETRTO 19-622 28 x 7/8" = ETRTO 22-622 28 x 1" = ETRTO 25-622