Kreg Zinc Screws are a good choice for a wide variety of indoor projects with limited exposure to the elements. Zinc screws provide adequate rust protection and serve as an affordable alternative to our more protective Blue-Kote and stainless screw varieties. #8 - All SML coarse-threaded screws (with the exception of stainless). #7 - All SML fine-threaded screws and all SPS coarse-threaded screws. #6 - All SPS fine-threaded screws. Available in a variety of sizes thread options head styles and quantities. Use the chart below to select the right screw type for your application.