Metal Grommets Kit: It is made of metal, strong, difficult to deform, durable and anti-rust, 12mm (1/2 in) inside diameter, 21 mm (4/5 in) outside diameter. Tools for eyelet washers: 100 sets of eyelets, (each set includes 1 eyelet and 1 washer), a drilling tool, a tight tool and storage box. Easy to use: make it easy to put on the eyelet eyelets with matching hole cutter and mandrel The mandrel has a distinctive pattern on the surface, non-slip provides more secure grips. With a plastic storage box: ideal for storing a small tool eyelets, easy to bring back and apply while sewing. Tensioned applications: Grommets can be widely applied to clothing and fabric, it is suitable for repairing tents, pool covers, tarps, canvas sails, or DIY craft projects.