A zipper consists of two strips of fabric tape, each affixed to one of the two pieces to be joined, carrying tens or hundreds of specially shaped metal or plastic teeth. These teeth can be either individual or shaped from a continuous coil. Some zips have two slides, allowing variation in the opening’s size and position. In most jackets and similar garments, the opening is closed entirely when one slide is at each end. In most baggage, the opening is closed entirely when the two slides are next to each other at any point along the zipper. Zippers are use to:: 1) Increase the size of an opening to allow the passage of objects, as in the fly of trousers or in a pocket 2) join or separate two ends or sides of a single garment, as in the front of a jacket, dress or skirt. 3) Attach or detach a separable part of the garment to or from another, as in the conversion between trousers and shorts or the connection / disconnection of a hood and a coat. 4) decorate an item. These variations are achieved by sewing one end of the zipper together, sewing both ends together, or allowing both ends of the zipper to come completely apart. A zipper costs relatively little, but if it fails, the garment may be un-wearable until the zipper is repaired or replaced — which can be quite difficult and expensive. Problems often lie with the zipper slider; when it becomes worn it does not properly align and join the alternating teeth. If a zipper fails, it can either jam (i.e. get stuck) or partially break off. Use the pictorial below to put in your lapped application zipper and your open application zipper.FREE SHIPPING on orders $35+ from Fabric.com