The width of the head width is related to the meshing width of the chain teeth, but when the chain teeth are engaged, it is not the tight fit between the metal parts and the metal pieces. They are loose space. The chain teeth of nylon zippers are less rigid, and when they are engaged, the compression wholesale zippers can produce a certain number of chain teeth deformation, including the size changes brought by the Angle changes after the meshing of the chain teeth. Therefore, when determining the width of the pull head, it is mainly based on the length of the length of the single chain tooth, and the length of the chain tooth is used to calculate the size of the meshing width, which can be calculated by the mathematical formula.The length of the flat part of the tail is limited to the length of the two teeth of the unilateral tooth chain, and the meshing relationship of the tooth chain is stable, and the meshing locking relationship is more stable with the continuous passing of the subsequent chain teeth in the pulping body.