The Grip Fast® triple-coated deck screws are made to last. With a state of the art coating guaranteed not to rust or corrode for the life of the project, and one of the thickest shank diameters on the market, they're built to perform. Triple-coated screws are designed with two layers of coating over a galvanized undercoating. For exterior use with redwood, cedar, and all treated lumber. Triple-coated screws are NOT recommended for marine or projects within five miles of coastal waters. So, whether you are building a fence, deck, or just using them for general use, trust in knowing that the Grip Fast® triple-coated premium deck screw will meet your expectations and more.