Production, processing, and sales of electromechanical products, field camps, mechanical parts, oil drilling equipment and accessories, water injection pump parts, petroleum pipes and fittings, lined pipes, oil and gas production aids (excluding hazardous chemicals), metal containers, environmental protection equipment, sludge and sewage treatment devices, AC low-voltage distribution cabinets (low-voltage switchgear assemblies), explosion-proof electrical equipment (excluding coal mines), rubber hoses and hose assemblies, metal wire ropes and products, lifting ropes, safety ropes, slings, specialized petroleum pipeline belts, other lifting rigging, wood and wood products, building materials (excluding hazardous chemicals), chemical products (excluding hazardous chemicals, precursor chemicals, and monitored chemicals); Drilling engineering, construction engineering, petrochemical engineering, fire protection engineering, earthwork engineering, cleaning of electromechanical equipment, anti-corrosion engineering, noise pollution control, sludge and sewage treatment and recycling, environmental protection engineering, municipal public engineering, water and electrical installation, building electromechanical equipment installation engineering, and complete lighting system engineering construction; Security engineering design and construction; Contracting services for precast concrete components, steel structure engineering, and building decoration engineering; Sales, installation, and after-sales service of fire and security equipment and devices; Oilfield water injection services; Installation, construction, and operation of new energy vehicle charging stations; Sales of mud pump parts, diesel generator sets and generator parts, petroleum machinery and accessories, polyurethane series products, automotive parts, hardware products, communication terminal equipment, furniture, daily-use sundries, and fracturing quartz sand; Petroleum engineering technical services, information system integration technical services, environmental protection engineering information consulting, and construction engineering labor subcontracting; Online trade agency; Housekeeping services; Property management; Repair of electromechanical equipment and vehicles; House and equipment leasing; General cargo road transportation; Accommodation (limited to branch operations); Export business of self-produced products, import and export of machinery parts and technology (subject to approval from relevant departments for licensed projects).