We can distinguish the shirt from the size of the jersey. The fancases (including offset and premium) sizes are: S, M, L, XL .... The youth version is written as: Youth S (8-10), Youth M (10-12), Youth L (12-18), Youth XL (18-20). The figures on the back indicate the appropriate wearing age. Player version size is: 44,48,52 ... .... 44 is equivalent to L code, 48 is equivalent to XL code, and so on. This estimate we do not quite understand, this American size is based on the bust of the inch to be set. For example, 44 yards is the bust 44 inches, equivalent to 112CM. To emphasize is that the genuine mass jersey size is 4-inch jump up. 52 up a size must be 56, then up to 60 (does not seem to be bigger). Occurrence 42,46,50,54 size only in the players wearing their own jersey (Pro-cut Jersey / Pro-worn Jersey) will appear. Taking the familiar NBA as an example, Jordan wore a 50-yard jersey for the Wizards. So in addition to 50 yards, the 46,54 size and other Jordan Wizards jersey is not possible. If you see this size, you can be sure that this shirt is fake! ! On the NFL jersey is the same reason.