The slider by the upper and lower cover plate through the core combined into and organic whole,The nylon zipper teeth on the chain produced by plastic zipper manufacturer are distributed asymmetrically on the tape,so the nylon zipper slider and lower cover plate edge to help size is asymmetric,the cover plate is long,the cover plate is short,in the middle of the pull head inside the cavity is equipped with a streamlined and convex rib,size is also different.The upper cover of the pull head is equipped with a pull nose to arrange the pull. There is a self-locking small file in the pull nose of the self-locking head, which can be automatically inserted into the gap between the production of the chain tooth under the action of the spring plate, which can be used to lock the pull head into a certain position of the chain belt.