R&D, production, and sales: dust-free cloths, junior high-efficiency filters and fan filter units, dust-free purification products, anti-static products, electronic product production lines, automation equipment, fixtures, stainless steel frame products (metal etching, spray painting, passivation, and electroplating processes are prohibited; production wastewater is prohibited from discharging phosphorus and nitrogen pollutants; radioactive, highly toxic, and high-risk dust is prohibited); purification engineering design, installation, and maintenance.