CONCRETE TUBE 10"X12' ECOFORM ECONO tubes, made of 100% recycled fiber, are robust and lightweight. For single use, they are ideal for multiple construction or renovation applications. Patio supports, fence posts, mailbox supports, mobile home or cottage supports, the uses are endless. They are intended for non-architectural use. The waxed inside surface of the ECONO tubes facilitates the above ground removal of the cardboard once cured. Similar to Sonotube.