The Gro Pro? Premium Anti-Spiraling Round Pots are large pots for growing large plants. They are high-quality injection molded, durable plastic pots. They are designed with specifically placed channels to prevent root spiraling, which encourages a more dense and fibrous root system. These containers have several aeration holes to air prune roots and allow for more oxygen into the root zone then a standard plastic container. Available in 180, 285 and 375 liter sizes.