Steel structure sales; Wholesale of environmental protection equipment; Sales of electrical machinery and equipment; Cooling tower sales; Sales of general machinery and equipment; Professional contracting of electromechanical equipment installation engineering; Wholesale of auto parts; Wholesale of metal products; Special equipment installation (except elevator and boiler); Lease of mechanical equipment; Mechanical and electrical equipment installation services; Wholesale of hardware products; Research and development of electronic, communication and automatic control technology; Electronic automation engineering installation service; Special equipment repair; Construction steel structure and prefabricated component engineering installation services; Installation service of building air conditioning equipment and ventilation equipment system; Professional contracting of foundation and foundation engineering; Construction of environmental protection facilities; Construction labor subcontracting; Engineering drainage construction services; Indoor stadium and entertainment facilities engineering services; Building equipment automation system engineering services; Interior decoration and decoration; Interior decoration design service; Decoration, decoration and cleaning in the later stage of the construction project; Intelligent installation engineering services; Professional contracting of fire-fighting facilities engineering; Building construction; Housing construction engineering design services; Environmental protection technology promotion service; Environmental protection technology development services; Environmental protection technology consultation and exchange services; Installation service of water transmission pipeline facilities; Research and development of water treatment equipment; etc.