Sales of metal products; Wholesale of hardware products; Sales of metal materials; Sales of metal structures; Sales of non-ferrous metal alloys; Sales of metal chains and other metal products; Sales of high-quality special steel materials; Sales of bearings, gears, and transmission components; Sales of metal wire ropes and their products; Sales of building materials; Sales of building decoration materials; Sales of steel reinforcement products for construction; Sales of metal fittings for construction; Sales of lightweight building materials; Sales of building blocks; Sales of building waterproofing membrane products; Sales of anti-corrosion materials; Sales of cement products; Sales of rubber products; Sales of plastic products; Sales of electrical equipment; Sales of instruments and meters; Sales of special equipment; Mold sales; Electronic product sales; Sales of mechanical equipment; Sales of valves and plugs; Operation of wires and cables; Wholesale of electronic components; Sales of mechanical parts and components; Sales of packaging materials and products; Sales of doors and windows; Sales of communication equipment; Sales of daily necessities; Sales of household appliances; Sales of labor protection equipment; Retail of computer software, hardware, and auxiliary equipment; Sales of office supplies;