... middle layer of aluminum, the expansion co-efficient a samll metal pipe with considerable strength, toughness, impact resistance.5. Corrosion- ... reach 95°C.7. Energy-saving insulation: thermal conductivity of metal pipes1/200 only, hot water pipe insulation for excellent energy ... force, soft color, and beautiful graphics.10. Can be buried, metal detectors can be used to detect the location of the tube ...