GRK 14231 5/16 in. x 5-1/8 in. Star Drive Washer Head Coated Steel RSS GRK RSS Rugged Structural Screw has a patented design and made of especially hardened steel to provide customers with high tensile, torque and shear strength. The sharp threads and points bite instantly into material, including hardwood, reducing the splitting effect due to smaller shanks. The GRK RSS series screws that are 3-1/8 in. and longer have six CEE threads which enlarge the screw hole for the non-threaded portion of the fastener, allowing the wood to settle easily and increases the screw's drawing strength. Features Built-in washer head Coated and hardened steel ICC report ESR-2442 Uses GRK bit T-25 Self-tapping USA SHIPPING estimates delivery times and we work to get your item to you as quickly as possible and within those times, but please know it may take slightly longer than the estimate.