Chicago screws: 5 sizes, 16 sets for each size, 80 pieces total. 5 different sizes: Post diameter is 5 mm; post lengths are 6 mm, 10 mm, 12 mm, 15 mm, and 18 mm; screw and base diameter is 9.5 mm. Storage box: Packed in a clear storage box with partitions organized by size for easy identification. Wide application: Suitable for leather crafts, bookbinding, documents, books, albums, and similar projects. Material: Carbon steel Color: Silver Package contents: 16 sets of Chicago screws (5 mm x 6 mm) 16 sets of Chicago screws (5 mm x 10 mm) 16 sets of Chicago screws (5 mm x 12 mm) 16 sets of Chicago screws (5 mm x 15 mm) 16 sets of Chicago screws (5 mm x 18 mm) 1 transparent storage box Note: Color may vary slightly due to lighting and screen settings. Measurement tolerance is ±1–3 mm.