GRK's patented Rugged Structural Screws are made of especially hardened steel to provide high tensile, torque and shear strength. Sharp threads and points bite instantly into building materials (including hardwood) - reducing the splitting effect due to smaller shanks. Featuring a round head with built-in shield (washer type head) which has no sharp edges such as on conventional lag screws. The added shoulder (nominal diameter) underneath the washer has the ability to center the RSS ® screw in pre-drilled hardware like hinges and connector plates. The unique design enables users to skip the pre-drilling, wrenching and pre-countersinking stages, thereby eliminating three of the four steps necessary when using ordinary lag screws. The RSS can considerably speed up the installation of the deck substructure and is ideal for constructing pergolas, landscape walls, newel posts etc...