How Does a Zip (Zipper) Work?

A zipper consists of two strips of fabric tape, each bearing a row of tiny teeth (metal, nylon coil, or moulded plastic). The slider has a Y-shaped channel inside. When pulled upward, the slider's wedge forces the two rows of teeth together so they interlock like clasped hands — each tooth hooks into the gap between two teeth on the opposite side. When the slider moves down, a separating wedge pries the teeth apart. The bottom stop prevents the slider from coming off, and a top stop does the same at the top. Modern zippers can handle over 10,000 open-close cycles. YKK, a Japanese company, manufactures roughly half of the world's zippers.