These sheet metal screws by Prime-Line Products are constructed of steel and come in a corrosion-resistant finish, enabling them to be used both indoors and out. The threads on sheet metal screws are designed to pull two materials tightly together. Pre-drilling is not necessary when using these fasteners, as they feature self-drilling and self-tapping points. The fastener drive type, size and grade vary slightly between fasteners of this type, while the ease of use and gripping strength do not.