Manufacturers may give the same item different model numbers in different countries, even though the functions of the item are identical, so that they can identify grey imports. Manufacturers can also use supplier codes to enable similar tracing of grey imports. Parallel market importers often decode the product in order to avoid the identification of the supplier. In the United States, courts have ruled decoding is legal, however manufacturers and brand owners may have rights if they can prove that the decoding has materially altered the product where certain trademarks have been defaced or the decoding has removed the ability of the manufacturer from enforcing quality-control measures. For example, if the decoding defaces the logo of the product or brand or if the batch code is removed preventing the manufacturer from re-calling defective batches.