The screws are made of carbon steel material, high hardness and with inner threaded design, being smooth and safe, sturdy and , to give good luster for better using. Non-rusting, not easy to rust in moisture environment, , can be widely used for leather handicrafts decoration, bookbinding, document, book, album, DIY crafts and more. Features - Color: silver. - Material: carbon steel. - Size: 0.90X0.50X0.40cm/ 0.35X0.20X0.16inch. - Specification: M4x4, M4x5, M5x5, M5x6, M5x8, M5x10, M5x12, M5x15, M5x18. - Made of carbon steel material, , anti-rust, safe and for long time to use. - These screws can be used for leather handicrafts decoration, bookbinding, document, book, album, DIY crafts and more. - Easy to bind, install and remove, can use repeatedly, good tightness, you can use rest assured. - Perfectly smooth, hard and thick, sturdy inner threaded design, not easy to fall off. - Delicately designed head, can be install and remove with standard screwdriver easily repeatedly. Package list: 85 x screws(M4x4) 30 x screws(M4x5) 25 x screws(M5x5) 20 x screws(M5x6) 20 x screws(M5x8) 10 x screws(M5x10) 10 x screws(M5x12) 10 x screws(M5x15) 10 x screws(M5x18)