(Authentic packaging is on the left)
The first thing you’re going to want to check is the packaging. This may be difficult to identify, as different sizes come in different size boxes, but fake pairs may either be in boxes that are too large or boxes that are slightly too small. Your pair should be sitting in a box that seems appropriate. This might sound vauge but if you have a retail pair and are looking to double up you should be able to check the box size.
The size label itself will be hard to LC, but the lid of the box should be very close to the label. There shouldn’t be a noticeable gap between the box lid and the size label.
Lastly is the paper inside. This one might sound kind of vauge but the paper needs to be in the “goldielocks zone”, aka not too thin and not too thick. Some fakes will have a thick paper that is a deep semi-gloss black while others will look like a garbage bag. Legit pairs will feature an almost smoky black paper that is kind of like a wax baking paper.
Keep in mind that most of these differences will be difficult to notice unless you have a retail pair to compair to!