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.

Most Nike items will follow this rule if it contains the small serial code label. Look underneath the wash tag to find this reference.

Locate the tag inside your shoe. All authentic Nike shoes have a tag sewn into them with their size, barcode and model number on it.