Durable for long-term use - High quality 304 stainless steel provides strength and good corrosion resistance in many environments. Surface Surface ;stress bearing- Have enough stress bearing surface which can be screwed tighter. Transparent case for quick access- All screws and nuts will be packed in a sturdy plastic box, this set is organized by size/type in a clear storage case for quick access and protection. Usage - Widely used in home and office appliances, communication equipment, ship assembly and other machinery industries, furniture, car and motorcycle repair and DIY inventions! Can also be used for storage box fastening component, industrial and construction fasteners. Ideal for use in confined areas where the head must be flush or below the surface. Basic Information Material - Material: 304 Stainless Steel / Drive Type: Hex Socket / Style Head Size: Button Head / Size: Different Size of M3 M4 M5 (Include M3 M4 M5 Nuts)