These screw posts are easy to use for binding and removing. You can use a drill to create a 5 mm diameter hole, then install the two parts from opposite sides. Made of carbon steel and brass for strength and durability, with a nickel-plated surface that enhances corrosion resistance and provides a decorative finish. Suitable for leather crafts, document decoration, bookbinding, photo albums, scrapbooking, and other DIY projects. Note: Different leather thicknesses require different screw lengths. 4 mm screws work best with 4–6 mm thick leather, 6 mm screws with 6–8 mm thick leather, and 8 mm screws with 8–10 mm thick leather. Please verify thickness before ordering. Material: Carbon steel and brass Color: Silver, Gold Sizes: All posts have a 5 mm (3/16 inch) diameter, with three length options—4 mm (0.16 inch), 6 mm (0.24 inch), and 8 mm (0.3 inch) Quantity: 10 pairs per set (20 pieces total) Note: 1 cm = 10 mm = 0.39 inch. Allow for 0–3 cm variation due to manual measurement. Image colors may vary slightly due to monitor differences. Package includes: 10 pairs of belt buttons