This is a fantastic little kit for anyone who loves DIY, sewing, leatherworking, or crafting! You get 100 pieces of small 4mm inner diameter brass grommets (eyelets) plus 100 matching iron washers. They're perfect for reinforcing holes and adding a professional finish to all kinds of projects. Use them on belts, shoelaces, bags, tarps, clothing, curtains, or scrapbooks. The kit also includes the installation tool (the 'rivet tool' or settter). How it works: 1) Punch a clean hole in your material. 2) Push the eyelet through from the front. 3) Place the washer on the back. 4) Use the tool and a hammer to press them together securely. They're made of durable metal and will last a long time. Whether you're repairing a backpack or creating something new, these grommets are an essential hardware supply to have on hand. Great value in a 100-piece pack!