The general business items are: sales of anti-static instruments and their consumables; design and construction of refrigeration and electrical engineering, dust-free purification engineering, steel structure engineering, air duct engineering, and HVAC purification engineering (the above must obtain a qualification certificate issued by the construction administrative department before operating); door-to-door installation and maintenance of purification equipment and refrigeration systems; domestic trade (excluding franchised, exclusively controlled, and monopolized goods); and import and export business (except for items prohibited by laws, administrative regulations, and decisions of the State Council, and restricted items must obtain a license before operating).