CARBON STEEL: Made of high-quality carbon steel, it features high strength, black treatment, wear resistance, and durability. COMPLETE KIT: The kit includes M2, M3, M4, and M5 bolts and nuts of four specifications. WITH SPACER: The kit is also equipped with suitable spacers to meet your different needs. WIDE APPLICATIONS: Widely used in electronics, hardware, lighting, toys, bathrooms, furniture, sports equipment, and other industries. TOTAL 1225 PARTS: The kit contains a total of 1225 pieces, enough for replacement and use. Comes in a plastic box for easy storage.