On the tongue in the original pairs from Nike There is the brand's logo. On the inside of the tongue on the tag should be product information, including size and country of manufacture. There is also a 9-digit serial number, which should correspond to the code on the box.

All authentic Nike shoes have a tag sewn into them with their size, barcode and model number on it. You will recognize it most easily by the barcode. Look for it inside: The tongue.