1. A2-70 Material: Using high quality A2-70 steel material, not easy to deform, very durable for long term use.2. Exquisite Workmanship: Adopting black zinc plating process, these countersinks are neat and reliable.3. Extensive Use: Allows flexible application of fasteners to various materials and also for connections.4. 50 Pieces in 1 Set: The set includes 50 pieces of flat screws, which greatly covers the replacement needs.5. Easy Installation: The M4 type allows convenient installation with a PZ2 screwdriver and is also very easy to carry.Specification:Item Type: Countersunk ScrewMaterial: A2-70Product Model: M4Standard: DIN 965Process: Black Zinc PlatedThread Diameter: Approx. 4mm / 0.16inPitch: Approx. 0.7mm / 0.03inScrew Head Height: Approx. 2.2mm / 0.09inHead Diameter: Approx. 7.3mm / 0.29inScrewdriver Size: PZ2Black galvanized explained. These screws are standard galvanized screws with a decorative black coating.The Dip Spin Black coating provides slightly increased corrosion protection and is very thin so it does not affect the threads. No deposits form in the threads or in recesses on the heads. The coating is solvent-based, chemical-resistant and also RoHS2 compliant. Please note, however, that due to the thin application of these screws, there may be minor scratches on the coating. Package List:50 x M4x16 screw