The Märklin toy company systematically included a print run number on almost all their printed material, including the boxes in which their products shipped. These print run numbers indicate the printer and also the month and year of printing. This is useful for dating an item that is known to be associated with some printed material. The second group of digits indicates the catalogue number. The last set of numeric digits in the print run number indicates the month and year that the item was printed. The last group of letters identifies the printer.