Construction, maintenance, industrial robots, maintenance of containers, furniture installation and maintenance services, maintenance of computers and office equipment, industrial engineering design services, industrial design services, professional design services, sale of mechanical equipment, installation of general mechanical equipment, sale of mechanical equipment, sale of construction engineering equipment, sale of electrical machinery, sale of gas-powered machinery and components, sale of gas-compressed machinery, leasing of machinery, construction engineering machinery and equipment, development of equipment, maintenance of electronics, mechanical equipment (without special equipment), metal chain and other metal manufacturing equipment, sale of general mechanical equipment, sale of metal chain and other metal equipment, sale of mechanical equipment, sale of electrical equipment, electrical and mechanical equipment, sale of electrical equipment, electrical equipment, electrical and mechanical equipment, sale of electrical equipment, electrical equipment, electrical equipment, electrical equipment and electrical equipment, sale of electrical equipment, etc., sale of electrical equipment;