Upgrade your heavy-duty projects with these 120 Pcs 5/16-18x2 1/2" Black Phosphate Trailer Floorboard Screws, engineered for unmatched durability and efficiency. Featuring self-tapping thread-cutting technology, these screws pierce wood, metal, or composite materials effortlessly, eliminating pre-drilling and cutting installation time by 50%. The included industrial-grade T40 star drive bit ensures maximum torque transfer, preventing slippage even under high pressure. Built with heat-treated carbon steel and a military-grade black phosphate coating, they resist corrosion 3X longer than standard zinc-plated screws, thriving in harsh weather, road salt, and chemical exposure. The 80° flat head design sits flush with surfaces, preventing cargo snags while maintaining structural integrity. Ideal for trailer decks, truck floors, agricultural equipment, and warehouse walkways.These wood to metal Screws delivers professional-grade reliability for both DIYers and commercial users.