Sale of mechanical equipment; Sale of metal materials; Sale of mechanical parts and components; Sale of instruments and meters; Sale of building materialsexcluding sand and gravel); Sale of building decoration materials; Retail of hardware products; Sale of labor protection supplies; Sale of rubber products; Sale of lubricating oil Sale of furniture; Sale of furniture parts; Retail of household appliances; Household appliance repair; Sale of office supplies; Wholesale of hardware products; Technical services, technical, technical consulting, technical exchange, technical transfer, and technical promotion; Research and development of mechanical equipment; Lease of mechanical equipment; Maintenance of electronic and mechanical (excluding special equipment); Repair of instruments and meters; Furniture installation and repair services; Installation service of household appliances. (Business activities that require approval according to laws regulations shall not be conducted without the approval of the relevant departments. )