Neoprene is a durable non-toxic rubber used to trap moisture and add support to plant stems.
These replacement inserts are made from tighter, more dense foam for more strength.
Neoprene inserts are designed to fit into net pots when gardening with aeroponic systems.
American Agritech Clone Machines would use the 2" Neoprene Insert.
General Hydroponics Aeroflo2 systems use the 3" inserts.
The 5" neoprene insert fits the Aerojet (Jet Gro) 4, 6 or 9 plant units -AND- the Turbogarden Aeroponic Hydrogarden.
Botanicare's Power Cloner uses the 1-5/8" neoprene collars.