A slider, similar to a zipper, is used to thread eyelets or tear edges, for example, on clothing or a bag. A zipper consists of two strips of webbing with metallic teeth along the edges and a slider that pulls the teeth into an interlocking position when moved in one direction and separates them again when moved in the other direction.
The most typical material for buttons is polyester, which is a type of plastic with properties that make it useful for buttons. Several chemical dyes are added to the polyester so as to make different colors. To make buttons with the pearlescent sheen of shell buttons, red carbonate is added to the polyester.