#12 X 3-1/2'' Stainless Flat Head Phillips Wood Screw, (25 pc), 18-8 (304) Stainless Steel Screws by Bolt Dropper

Despite their not-so-small dimensions, these screws go in easily, even into tight holes, with either a drill or a manual screwdriver. I used these long and strong screws to attach flag holders to the walls (where other screws did not hold in strong winds). And the screws have held up, still looking like new even after several years in a windy place with high humidity and salt from the ocean. High-grade stainless steel makes these screws resistant to corrosion. Although the product name says "Wood Screw", these screws are suitable for a broader range of applications, including fastening in concrete, brick, and stone through plugs, both indoors and outdoors. I also want the same screws with round, binding, and tusk heads.