Choose the tube you like according to manufacturer and valve type/length
Presta/French: thin, metal valve with a little security top part which needs to be unscrewed by hand before attaching the pump or head of the hose, and tightened again afterwards to prevent air from slowly leaking out of the tyre. (FV or S)
Auto/Schrader: the most common type of valve and acts in the same way as car valves, so you can inflate directly (AV või A).
Dunlop/German: wider lower section, like the Schrader, and a narrow top section, like the Presta (GV).
Italian: thin like presta, you can entirely remove the valve top.
26" = 559