GRK PHERSS516518HP RSS SS HandyPak 5/16 by 5-1/8-Inch Structural Screws, 50 Screws per Package PHEINOX Stainless Steel with limited lifetime warranty Use GRK Bit T-30 Self-Tapping W-cut thread design CEE Thread design in sizes 3-1/8-Inch and larger Lag Screw Alternative