General project: Manufacturing of metal materials; Import and export of goods; Technology import and export; Import and export agency; Spray processing; Metal surface treatment and heat treatment processing; Sales of metal materials; Electronic product sales; Sales of building materials; Sales of building decoration materials; Sales of metal fittings for construction; Maintenance of electronic and mechanical equipment (excluding special equipment); Sales of daily necessities; Mechanical equipment research and development; Mechanical equipment leasing; Sales of building waterproofing membrane products; Sales of chemical products (excluding licensed chemical products); Sales of lightweight building materials; Operation of wires and cables; Wholesale of electronic components; Wholesale of hardware products; Retail of hardware products; Tool sales; Sales of mechanical and electrical equipment; Fiber optic cable sales; Sales of generators and generator sets; Sales of metal wire ropes and their products; Sales of wind and electric tools; Sales of communication equipment; Sales of mobile communication devices; Sales of drug testing instruments; Sales of specialized chemical products (excluding hazardous chemicals); Sales of Class I medical devices; The first type of medical device leasing; Sales of daily masks (non-medical); Production of daily masks (non-medical); Wholesale of protective equipment for medical staff; Retail of protective equipment for medical staff; Domestic trade agency; Installation services for ordinary mechanical equipment; Sales of Class II medical devices; Wholesale of medical masks.