Grommet kit: Includes 100 piece grommet kit (with 100 grommets and washer, individually wrapped in PE bag), punch tool and attached tool, all in a damage-free plastic box. Size: Internal diameter: 12 mm (1/2 inch) and outside diameter: 21 mm (5/6 inches). With plastic storage box, approx. 6.9 x 3.9 x 1.3 inches / 14 x 8 x 3.3 cm. Excellent material: The eyelet kits are made of quality copper-nickel and surface galvanized, with high corrosion resistance and a shiny appearance, very difficult to oxidize. Easy to use: The eyelet kit facilitates installation. First use the punch tool to punch a hole in the tarp (fabric), then take the set of eyelets and finally secure the set of eyelets with the attach tool. Please put rubber pad or wooden board when drilling holes to prevent the puncher from foaming. Wide range of uses: The grommet kit is suitable for canvases, tarpaulins, tents, curtains, backpacks, leather crafts, repair and decoration. (Materials with a thickness of less than 1 mm) .