The Tolsen 54173 is a self-drilling screw designed for fastening sheet metal steel, aluminum panels, roofs, and facades. These screws feature a specialized tip that eliminates the need for pre-drilling, which allows you to work faster and more efficiently on construction sites. Each piece has a diameter of 3.9 mm and a length of 25 mm, providing a secure hold in thin-walled materials. To ensure durability against corrosion, the screws are finished with a zinc-plated coating. The countersunk head allows the screw to sit flush with the surface, while the Phillips cross-head drive ensures a reliable grip for your screwdriver or power tool. This pack contains 500 pieces, making it a practical choice for professionals or DIY enthusiasts tackling larger installation projects.