Duct specially manufactured for absorbing air with contents of powder and harmful gases produced by mining works, tunnel constructions and civil works. They support high negative pressures and resist tears produced by the works.

Duct specially manufactured for insufflating air in tunnels and galleries in large volumes. It supports strong effective pressures of work, and its structure and material are resistant to the tear produced by the works and handling.  

This duct is ideal for conveying high working pressures of air to hard-to-reach places. Used in galleries and penetration tunnels (roads and hydroelectric plants) to facilitate air conduction in curved or uneven areas. These sleeves do not lose their cross section because the steel helix reinforcement provides this consistency, ideal for fan adapters that generate turbulence.