Recently,an online content for “ball pen can be easily torn bags zipper”articles on the internet,and at that time,many people question the zipper bag zipper really so vulnerable,suitcases and bags,guaranteed safe?Many of the suitcases on the market are zipper suitcases,some with a password lock,According to the luggage store owner,the suitcase zipper material is basically divided into nylon,plastic and metal.The zipper of the suitcase at about Rmb 50 yuan is made of plastic material,the zipper and the box are soft fabric,and the suitcase with a price of about 100 yuan,the zipper material is mostly resin.The zipper for the 400 yuan suitcase is made of metal,with a higher safety factor. The prototype of the zipper is “self-locking”,The zippper has two rows of interspaced chain teeth,each of which has a convex concave,when we pull zipper pull head leads on both ends of the teeth,in the middle of the pull head stack in succession:chain on the convex concave fold to the below chain tooth,the concave is folded to the chain sprocket above on the convex teeth,tooth arrangement form a comtinuous chain of the occlusion.