... life of 60 years; (2) hard with a metal pipe, but also easy to bend and straighten ... having to heat; (3) high temperature high pressure, pipe deformation, through the wall safe buried; (4) Temperature ... is -40 °C to 110 °C, high temperatures with high resistance to temperature strength; (5) outer wall ... smooth, fluid resistance, connected by pipe hot-melt, melting into one, does not leak, ...