Aj4 gray mouse has a black line.

A black line of AJ4 squirrel shoes is the sole reinforcement line, which cannot be cut. The function of this thread is to prevent the upper from separating from the sole, and to increase the firmness of the shoe by sticking the sole. If you cut this thread, the thread end will easily slip off and the sole will easily fall off. Therefore, when wearing shoes, you should protect your shoes and avoid overstretching or trimming the reinforcement lines in your shoes.