GRK PHERSS516212HP RSS SS HandyPak 5/16 by 2-1/2-Inch Structural Screws, 100 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