They are three types of filters are available: AquaMax and AquaClassic – standard filters remove chlorine and limestone; AquaPro are alkalizing filters, raise the pH of water and reduce ORP.
Each filter type is designed for a different kind of jug, AquaPro filters fit only into Wessper AquaPro jugs, while AquaClassic and AquaMax match jugs of different brands, before selecting you should check in the product specification whether they match the selected model.