Changsha Changsha County HunanNo.19 Tu Jian EngineeringNo.19 Tu Jian Shi EngineeringNo.21 Metal Pipes RoadNo.22 Steel PipesNo.23 Industrial ProductsNo.35 PipesNo.38 ConcreteNo.39 Road Road and Bridge BeamNo.42 Plain MaterialsNo.43 Di Ji Ji ChuNo.45 WoodNo.56 Waterproofing EngineeringISO9001认证