Used for stitching metal or attaching to metal. A pre-drilled hole is required. Countersunk head gives a discreet finish into pre-countersunk holes Plated in Trivalent Chromium (Cr3) Zinc 60 self-tapping thread for ease of insertion Manufactured to BS 4174:1973" Gauge: 12 Length inch: 1 1/2 Thread Dia. mm: 5.5 Length mm: 38 Head Type: Countersunk Recess Type: Pozi Point Type: AB Point Driver Bit Size: PZ3 Finish: Zinc & Clear Cr3 Material: Carbon SteelSize 12 x 1 1/2 - 100 Pieces Timco Metal Tapping Screws - PZ - Countersunk - Self-Tapping - Zinc in Silver