In addition to the fabrics used for the main school bags, the zipper knowledge in the custom processing of school bags when custom processing school bags. It is also necessary to pay attention to the application accessories of school bags, such as zippers. The zipper may seem inconspicuous, but it is a very important part, which directly affects the access of items and is related to the practical performance of school bags. The zipper is composed of elements, sliders, upper and lower stops (front and rear), or locking parts, among which the elements are the key parts, which directly determine the side pull strength of the zipper. Generally, the zipper has two pieces of chain belt, each chain belt has a row of fastener elements, and the two rows of fastener elements are arranged in a staggered manner. The fasteners on both sides are clamped by the slider, and the fasteners on both sides can be engaged or disengaged by sliding with the help of the pull tab. The zipper is a connecting piece that relies on the continuous arrangement of the chain teeth to combine or separate the items. Almost every school bag needs to use a zipper. The use of the zipper is very extensive and convenient. According to the data and shape of the zipper teeth, they can be divided into metal zippers, plastic zippers, nylon zippers, etc. The zipper is generally represented by the number (the width of the teeth when the teeth are closed in millimeters). The thicker, the greater the fastening force, and the performance of zippers of different types and materials are also different. A zipper can be divided into low, medium, and high quality, and the most suitable zipper can be selected according to the budget of the customized school bag. If it is a low-end school bag, the zipper used requires a slightly lower quality. On the contrary, if it is applied to the zipper of a high-end school bag, the requirements are a little higher. A slightly lower quality zipper is placed on a high-end school bag, except that it will cause an explosion. In addition to the chain situation, it will also affect the grade of school bags.