Galvanized screcoating which makes them resistant to corrosion. They are especially suitable for use on treated lumber, because the chemicals used to treat lumber can have a corrosive effect on steel screws. These by one of two methods: electro-plating, or hot-dipping.Shop, read reviews, or ask questions about Tapping Screws at the offici 1968, West Marine has grown to over 250 local stores, with knowledgeable Associates happy to assist. Shop with confidence - get free shipping to home or stores + price match guarantee!Self Drilling Screws (sometimes called self-tapping screws) are perfect for use in sheet metal steel, aluminum, wood, plastics, and other similar materials, self-drilling makes pre-drilling unnecessary. Additional Info : Color Black Buy on Amazon 2.Phillips Head Tapping Screws Phillips Head Tapping Screws - Factory, Suppliers, Manufacturers from China. Our business puts emphasis over the administration, the introduction of talented staff, plus the construction of employees building, striving hard to boost the standard and liability consciousness of staff members.