Mainframe tubes are hard wearing and durable and are ideal for creating fruit cages, crop cages, plant supports, pond covers, aviaries and pet enclosures. The tubes are made from extruded aluminium and designed with a small external diameter of 16mm so that their visual appearance is less obvious, even though the wall thickness is 1.6mm. These high quality 16mm aluminium tubes are used for all Mainframe structures and are compatible with all Mainframe connectors and accessories.