Sales of fluid control equipment; design, manufacturing, and installation of mechanical and ship piping systems; cleaning services; product system testing services; technical research and development, design, production, manufacturing, installation, repair, and on-site commissioning services for hydraulic equipment, pneumatic equipment (special equipment), and lubrication equipment; production and sales of hydraulic, pneumatic, and lubrication system components, technical consulting, installation, and repair; leasing of mechanical equipment; import or export of goods and technology (excluding those prohibited or subject to administrative approval by the state); domestic general trade; marine engineering design, construction, and technical consulting; manufacturing of railway rolling stock parts; installation, modification, and repair of marine equipment and port machinery; ship repair.