Conduit type DMC HJT-L is developed to offer together with high mechanical protection to traction, compression and crash, also thermic protection in particular aggressive environment in presence of flames, splashes of metal or of melted glass, steam water. The external recovering is made up by a mineral fiberglass, with a silicon elastomer, that can resist to exercise temperatures range -60°C + 260°C. Flexible hot deep galvanized steel conduit , reinforced clutch, before recovered of smooth ABT PVC -40°C +105°C heavy bore coating and well anchored to the metal conduit and after of silicon elastomer with fiberglass. Excellent flexibility to low temperatures, good resistance to atmospheric agents: (UV rays, ozone) good compatibility with most of insulating paints of “H” class. Self-extinguishing according to norms CEI EN 61386.