General equipment repair; Special equipment repair; Mechanical parts and components sales; Engineering technical services (excluding planning management, survey, design, and supervision); Environmental protection monitoring; Environmental protection special equipment manufacturing; Environmental protection special equipment sales; Metrology technical services; Technical services, technology development, technical consultation, technical exchange, technology transfer, and technology promotion; General mechanical equipment installation services; Instrument repair; Electrical equipment repair; Labor services (excluding labor dispatch); Professional cleaning, washing, and disinfection services; Loading and unloading; Engineering management services; Metal surface treatment and heat treatment processing; Fire protection technical services; Refining and chemical production special equipment manufacturing; Refining and chemical production special equipment sales; Mechanical equipment research and development; Electronic and mechanical equipment maintenance (excluding special equipment); Metal product repair; Metal cutting processing services; Safety technical training for special operations personnel; Earthwork construction; Road cargo transportation of general freight vehicles with total mass of 4.5 tons and below (excluding network freight and dangerous goods); Chemical product sales (excluding licensed chemical products); Special equipment sales; Anti-corrosion material sales; New material technology research and development; General valve and cock manufacturing (excluding special equipment manufacturing); Mechanical parts and components processing; Non-residential real estate leasing; Mechanical equipment sales; Mechanical equipment leasing; Industrial control computer and system sales; Special equipment leasing. Permitted items: Construction engineering construction; Special equipment manufacturing; Special equipment installation, modification and repair; Installation, repair and testing of power transmission, supply and reception facilities; Inspection and testing services; Electrical installation services; Specialized construction operations