One-piece heavy duty concrete screws with ETA Option 1 approval. Provides a strong hold for high load applications. DeWalt Hex Head Blue-Tip Concrete Screwbolt M10 x 100mm (25 Pack) in Silver. This pack of Hex drive recess hex head masonry screws are constructed from a durable metal, 100mm in length and come fully threaded. They're ideal for a range of DIY applications.