Textile and coating make up a unique fabric and the suspension system makes the duct even stronger. The suspension system with its plastic eyelets is also unique and employs a strong continous suspension rib, which runs along the length of the ducting and s welded on. The plastic eyelets contribute to the overall strength of the system. Ventilation ducts in mines and tunnels are exposed to extreme stress, including pressure waves caused by blasting, which put everey part of the construction on the test. Protan use plastic eyelets, which are stronger than brass eyelets. The eyelets have a standard spacing of 0.5 metres, which provides optimum flexibility during installation.