Manufacturing of power distribution switchgear equipment; research and development of power distribution switchgear equipment; sales of power distribution switchgear equipment; manufacturing of testing machines; sales of testing machines; manufacturing of electronic components; sales of power electronic components; manufacturing of electric motors; manufacturing of mechanical and electrical equipment; sales of mechanical and electrical equipment; sales of railway rolling stock parts; sales of electrical instrument meters; sales of coatings (excluding hazardous chemicals); sales of charging piles; sales of lubricating oils; sales of batteries; sales of rail transit engineering machinery and parts; sales of high-speed rail equipment and accessories; sales of mechanical equipment; sales of advanced power electronic devices; leasing of mechanical equipment; repair of electrical equipment; installation services for general mechanical equipment; industrial engineering design services; labor services (excluding labor dispatch).