Watertube was a Fremen device of wide application in the transfer of liquids. Watertubes existed since the final stage of the Zensunni migrations. Its sophisticated design is an example of the Fremen attention to minute detail. The close investigation prompted by scattered comments in the Dunebook, revealed sophisticated attention to details of watertube design and manufacture behind its simplistic appearsance, which in turn confirms the extraordinary importance of water conservation in the desert environment of Arrakis