Manufacturing of refrigeration and air conditioning equipment; sales of refrigeration and air conditioning equipment; manufacturing of gas compression machinery; manufacturing of household appliances; sales of household appliances; manufacturing of electronic components; wholesale of electronic components; retail of electronic components; research and development of household appliances; retail of daily household appliances; sales of household appliance parts; manufacturing of electrical accessories; sales of electrical accessories; manufacturing of plastic products; plastic products Sales; sales of metal products; research and development of metal products; manufacturing of power electronic components; sales of power electronic components; manufacturing of mechanical and electrical equipment; sales of mechanical and electrical equipment; sales of special electronic equipment; manufacturing of special electronic equipment; production of furniture spare parts; sales of furniture spare parts; manufacturing of teaching models and teaching aids; sales of teaching models and teaching aids; import and export of goods