Mechanical and electrical equipment processing; Mechanical parts processing; Mechanical and electrical equipment manufacturing; Mechanical and electrical equipment repair and maintenance services; Mechanical and electrical equipment sales; Mechanical and electrical equipment design; Mechanical and electrical equipment research and development; Mechanical seal manufacturing; Mechanical parts processing; Electronic and electrical machinery special equipment manufacturing; Metal surface treatment machinery manufacturing; Engineering Machinery manufacturing; Wholesale of machinery parts; Sales of machinery parts; Sales of general machinery and equipment; Sales of machinery parts; Retail of general machinery and equipment; Retail of machinery parts; Production of Beidou satellite navigation application terminal equipment; Sales of Beidou satellite navigation application terminal equipment; Sales of Beidou satellite navigation application terminal equipment After-sales service; research and development of Beidou satellite navigation application terminal equipment; wholesale of communication equipment and supporting equipment; wholesale of communication terminal equipment; wholesale of communication equipment; repair of communication equipment; manufacturing of general instruments and meters; manufacturing of components and devices for general and special instruments and meters; repair of general equipment; research and development of communication equipment; communications Research and development of terminal equipment; research and development of electronic products; research and development of electronic instruments; research and development of communication products; research and development of communication products; research and development of mechanical and electrical products; sales of general instruments and meters; operation of small household appliances; self-operated and agent import and export of various commodities and technologies, except for commodities and technologies that are restricted by the state or prohibited from import and export.