what are grommets used for
Grommets are used to reinforce holes in leather, cloth, shoes, canvas and other fabrics. They can be made of metal, rubber, or plastic, and are easily used in common projects, requiring only the grommet itself and a means of setting it with a punch, a metal rod with a convex tip. A simple punch, often sold with the grommets, can be struck with a hammer to set the grommet.