Distinction: look carefully shoe above the logo ( product ID ) and authentic has a little difference, but not a big issue. For quality detection of substandard shoes will play the last red B marker, and then destroyed. So B product is quality defective authentic. Really called B products, regular detection time generally have a B logo ( but do not rule out the special outflow ). In the part of detection or destroy air max trainers, internal staff will be B contraband out underground circulation to the market, there is a situation in which, testing personnel will be part of quality shoes ( A ) also to fight B mark or confused, so it is easy to smuggle out.