A trouser zip, also known as a zipper, is a common type of fastener used to secure the opening of trousers. It consists of two interlocking rows of teeth that are pulled together by a slider. When the slider is pulled up, the teeth engage and the zip is fastened. When the slider is pulled down, the teeth disengage and the zip is opened.
Trouser zips are an important part of a pair of trousers, as they allow the wearer to easily put on and take off the trousers. They are also important for keeping the trousers securely fastened, preventing them from falling down. Trouser zips are typically made of metal or plastic, and they come in a variety of sizes and styles.