ANSI hex head wood screws 5/16*2-1/2 (+3 Cr black) 1.standard:ANSI 2.material:35ACr 3.grade:5 4.finishing:+3 ... Cr ,black zinc ANSI hex head wood screws 5/16*2-1/2 ... steel,35CrMo,35#.etc.2.Size:1/4-1''3.Standards:DIN ,ANSI/ASME,BS,GB,JIS,Non-standard,JB/T4.Surface ...