The sneaker world is a booming industry, but it’s also a lucrative one for counterfeiters. Sales of knockoff goods reached $520 billion last year, accounting for 3.3% of global trade.

With this in mind, it’s important to know how to identify fake shoes. Here are a few tips to help you make an informed decision.

Reverse Engineered

Reverse engineering is the process of examining and then reconstructing an existing product to make it new. A common practice in the automotive, mechanical designs and even the microchip industries, reverse engineering entails taking an existing product apart to see how it works and what makes it tick.

The most common types of reverse engineering are forensic investigations into the manufacturing of a product or component. The most efficient way to go about this is with a combination of computer aided design (CAD) and high-tech measurement equipment. A CAD system is used to create 3D wire frame images of an object, allowing for the most accurate reproduction of a previously manufactured item.

There is also a sub-category of reverse engineering known as simulacra, which is the process of turning a design that was conceived as a simulacrum into a real thing. In a nutshell, it’s the simplest way to produce a replica of a real item, with little or no risk of losing out on a contract.

Too Good to Be True

When it comes to sneakers, a price that seems too good to be true is often a sign that something’s wrong. Authentic shoes are generally very expensive, so if you see a pair of Nikes that’s available at a bargain price, be wary.

Likewise, if you see an Adidas sneaker that costs less than a hundred bucks, it might be fake. Fake shoes tend to cut corners in order to save money, so you should check for any sizing issues or a difference in the materials.

Another way to spot fakes is to check the tag inside the shoe. This tag will tell you the product number and when it was made.

Similarly, you can also check the SKU code. This is a unique code that’s used to identify every single branded shoe.

Heel Tabs

Heel tabs are a common feature in shoes designed to accommodate heel striking. They cradle the heel and protect the Achilles tendon from abrasion. They also help support the foot and make putting on shoes easier, particularly for tight-fitting models intended for races or workouts.

Authentic pairs have a tab that’s textured and has little bumps in it, fake ones don’t. The tab on the fakes is glossy and doesn’t have a texture to it.

Another important detail to look out for is the stitching on the shoe. Stitching is a great way to associate Yeezy fakes with real ones, since it requires meticulous and accurate machinery that counterfeiters cannot afford.

The netting on a genuine pair is vibrant, has vivid bumps and has a slightly larger size than the fakes. The slits in the midsole are slightly wider, see yellow circles on the picture above.

Materials

There are several different types of materials used in fake shoes. For example, a fake Nike sneaker might have a leather upper but a synthetic sole.

Counterfeiters may use cheaper substitutes or cut corners to save money. In general, the material of a shoe is a good indicator of whether it’s authentic or not.

It’s also important to look for small details, which can be overlooked in the rush to get a new pair of shoes. For instance, if the logo on a fake pair is placed in the wrong position or if the stitching is a little off, it could indicate a fake.

The SKU code, or stock keeping unit code, is also a great way to identify fake shoes. Often, these codes can be found on the box or inside the shoe itself.