Research and development of metal products; repair of metal products; sales of metal products; manufacturing of metal structures; sales of metal structures; industrial engineering design services; sales of building materials; manufacturing of new building materials (excluding hazardous chemicals); sales of anti-corrosion materials; manufacturing of thermal and sound insulation materials; sales of thermal and sound insulation materials; engineering management services; manufacturing of building blocks; sales of building blocks; wholesale of hardware products; sales of labor protection supplies; road cargo transportation for general freight vehicles with a total mass of 4.5 tons and below (excluding online freight and dangerous goods). Licensed items: construction engineering construction; construction engineering design; specialized construction operations; interior decoration; construction labor subcontracting; installation, modification, and repair of special equipment.