PACKAGE: grommet tool kit 1/2 inch is well packed with a plastic clear case, great for storing small grommet, convenient to fetch and apply. APPLICABILITY: grommets kit provides an economic solution for repairing tarps, tents, awnings, curtains, canvas, leather and fabric, our grommet tool is also ideal for decoration for clothes, bags, crafts projects etc. OPERATION: grommet kit is easy to install, you only need to hammer the eyelet and washer together directly by our tools. EYELETS SIZE: inside diameter is 1/2 inch (12mm), outside diameter is 4/5 inches, barrel height is 1/4 inch. COMBINATIONS: grommet tool kit includes a base, a mandrel, a hole punch and 150 sets of grommets (150 eyelets and 150 washers).