The re-sale (sale without transformation) of goods to business units and to institutions and government. Importers and exporters; manufacturers' sales offices and agents; commission merchants and commodity brokers; commodity exchanges, petroleum bulk stations; assemblers and buyers of farm products and cooperative agricultural marketing associations. To include the re-sale of industrial and construction materials, machinery and equipment; farm machinery, implements and supplies; and business and professional equipment. Warehousing, grading and sorting, breaking bulk and re-packing, except in airtight containers, which is associated with reselling is also included.