Steel structure manufacturing, processing, and installation; manufacturing, sales, and installation of mechanical equipment, environmental protection equipment, non-standard equipment, and Class III low and medium pressure vessels; contracting of pipeline and metal door and window projects; manufacturing, sales, and installation of lifting equipment and accessories; manufacturing and sales of boilers, boiler auxiliary equipment, and heat exchangers; sales of metal materials, water heating equipment, building materials, instruments, meters, valves, steel, pipe fittings, hardware, electrical appliances, wires, and cables; leasing of mechanical equipment (excluding agricultural machinery) and vehicles; leasing of self-owned properties; self-operated and agent import and export of various goods and technologies (excluding goods and technologies restricted or prohibited by the state). General items: technology promotion services.