GRK *EACH* 5/16" x 6" RSS™ STRUCTURAL Screw #96015 T-30 | GRK’s RSS™ Rugged Structural Screw is a structural fastener designed for ease of installation and the strongest of connections. RSS fasteners drive into most woods without the need for pre-drilling. The specially engineered design results in a low-effort installation, especially compared to conventional lag screws.