• 300-piece sealing washer kit made of high-quality red copper. • Assortment of 12 sizes including M5, M6, M8, M10, M12, M14, M16, and M20. • Material with high conductivity and resistance to corrosion and high temperatures. • Provides a larger bearing surface to distribute the load and prevent breakage in fixings. • Suitable for electrical connections in appliances, automotive, boats, and hydraulic couplings. • Includes a practical and organized storage case with labels to easily identify sizes.