The plant cloning collars are suitable for use with Nutriculture net pots. They fit in the top of the pots and keep your young plants upright and strong while they grow out their roots. The products are made of top quality neoprene for optimum stability and support. The black collars don’t retain any amounts of water. They’re 100% waterproof. Your plants will grow strong and healthy in Nutriculture systems such as the Amazon. The indispensable spares units are environmentally friendly and you must replace them every two years.