Used For Stitching Metal Or Attaching To Metal. A Pre-Drilled Hole Is Required. Countersunk Head Gives A Discreet Finish Into Pre-Countersunk HolesPlated In Trivalent Chromium (Cr3) Zinc60° Self-Tapping Thread For Ease Of InsertionManufactured To Bs 4174:1972PTDTIM00101CCAZS