Every pair of authentic Nike shoes comes with an SKU number that is identical to the SKU number on their box. If the numbers are missing or do not match, they are likely fakes. Check the tongue label. Often, fake Nike manufacturers put outdated sizing labels on the inside of the shoe.

In 1971, Nike got its first shoe nicknamed the 'Moon Shoe' which was made in a waffle iron. The grid-like pattern of the waffle iron was replicated on the sole of the shoe. It was 1971. An ex-college runner, Phil Knight, and his coach, Bill Bowerman, started a small company known as Blue Ribbon Sports.

If you haven't worn the shoes out completely, you should be able to find inside each shoe a tag with a upc barcode as well as a number. That number is the identifying number for the model.