• Material: Made of high-quality carbon steel, resistant to corrosion, rust, and high hardness. • Content: Includes a total of 510 pieces distributed in 255 self-locking nuts and 255 metal washers. • Sizes included: Complete assortment of sizes M2, M3, M4, M5, and M6. • Functionality: Security nuts prevent accidental loosening and washers distribute pressure to protect connection parts. • Organization: All pieces are delivered in a storage box for easy organization and access. • Applications: Suitable for use in electrical connections, mechanics, automotive, industry, and maintenance and installation tasks.