These Stackable Support Poles are made from sturdy plastic and can filled with any substrate you want! Fill them with sphagnum moss, perlite, coco chunks, LECA, or our Chunky Potting Mix and watch the aerial roots grow like crazy. The Stackable Support Poles are sturdy and easy to assemble. Dimensions: * MINI: 12" Tall * SMALL: 14" Tall * MEDIUM: 16" Tall * LARGE: 22" Tall