High quality materials: All computer screws are made of high-quality brass, steel, and fiber paper. The steel plated with nickel and black zinc has excellent rust and oxidation resistance. Different types: 228 computer cases, power supplies, motherboards, hard drives, fans, brass bracket mounting screws, and insulation washers. Sufficient quantity: Our set has a total of 228 screws. The quantity is sufficient and the variety is complete, you can use it with confidence. Easy to store: These screws are all packed in plastic boxes for easy storage and preservation. Widely applicable: These hard drive screws are very suitable for fixed installation of PC chassis, power supplies, motherboards, hard drives, fans, and floppy disk/CD-ROM/DVD-ROM drives. Material: Metal Quantity: 228 pieces The package includes: Mainboard standard copper pillars (M3 6+6): 24 pieces Mainboard insulation gasket (red M3 8): 30 pieces Mainboard fixing screws (M3 5): 30 pieces CD-ROM fixing screws (M3 4): 30 pieces Hard disk screws (M3.5 5): 30 pieces Chassis hand screw (silver M3.5 5): 6 pieces Chassis hand screw (black M3.5 5): 6 pieces High strength screws (M3.5 6) for chassis: 24 pieces Regular chassis fan fixing screws (white zinc M5 10): 24 pieces Traditional chassis fan fixing screws (black M5 10): 24 pieces