PPR pipes are co-extruded by high-tech Nano-antimicrobial materials, allowing an attractive appearance, solid structure and smooth pipe walls (including the interior and exterior wall). Besides, PPR pipe or pipe fitting enjoy a small thermal conductivity, which is only 0.5 percent of that for metal pipe. Therefore, when used in hot water supply systems, they have an excellent thermal preservation effect. PPR pipes and pipe fittings are connected perfectly by heat fusion, which avoids water seepage.