In some cases, they are encoded to carry information about the product, such as date of manufacture, model type, etc.identify a shoe, providing the characteristic was sufficiently clear and detailed, and reflected sufficient significant features in common with the scene impression. In most instances, they are simply a sequential number, which describes how many units in a particular production sequence have been produced. They are used to distinguish items from others of a similar appearance. Serial numbers are present on many everyday objects.
