60mm diameter Metal tube gets filled with porus drinded hydrophonic stones. do not use ton , these tinz red balls because thru the airgaps too much water in the reservoa will vaporise, use the grinded material instead. No PUMPS ARE NEEDED!! the material is so porus it will deliver enough in even taller highs! fill the tube, fill in the water and do not care about buying salads anymore!! Have Phun !