Packing: 12pcs Material: zinc alloy Colour:blue and black Size: 13mm(0.51inch) diameter, screw: 7mmx3.5mm Sturdy, anti-corrosion, durable, not easy to fade, can be used for a long time. Smooth surface, bright colour, not easy to rust, light weight. How to use:First drill a hole with a punching tool, put the rivet on the punched hole, then use screws to fix it, easy to install and remove. Suitable for wallets, belts, hats, wristbands, shoes or jeans, hair bands, DIY leather crafts and so on. It can also be used as a gift for people who like DIY leather crafts.