Multi-mode fibres are used the most often (though there is nothing to prevent from the use of SM fibres, especially with reduced bending radius). The outer cover is made of flame retardant material, with low smoke emission and halogen-free (LSOH), so that they can be used in enclosed spaces, railway tunnels, road, etc. They are fully dialectic and resistant to electromagnetic interference. They are also flexible and easy-to-install, and can be placed in the vicinity of electrical systems. In order to build a network in multi-storey buildings, we offer easy access cables whose design enables pulling 20 m tube/module from a cable, and access to fibres without tools.