Grip-Rite Flat Washer Head Structural Screws are a versatile fastener intended for use in load bearing exterior construction projects. With our premium PrimeGuard Plus coating, these structural screws are guaranteed to last the life of your project. Grip-Rite Flat Washer Head Structural Screws are engineered with the power needed to replace lag screws. With a T 17 point and aggressive coarse threads, installation is a seamless process that doesnt require pre-drilling. Perfect for use with a variety of materials, including wood, composites, and light gauge metal, in structural applications. Our flat washer head fasteners use a star drive type for secure connection between the tool tip and fastener for a strong connection.