Used for stitching metal or attaching to metal. A pre-drilled hole is required. Flange head gives an aesthetic finish whilst increasing the clamping ability of the screw 60 self-tapping thread for ease of insertion Manufactured to BS 4174:1972" Gauge: 8 Length inch: 3/8 Thread Dia. mm: 4.2 Length mm: 9.5 Head Type: Flange Recess Type: Pozi Point Type: AB Point Driver Bit Size: PZ2 Finish: Zinc & Clear Cr3 Material: Carbon SteelSize 8 x 3/8 - 200 Pieces Timco Metal Tapping Screws - PZ - Flange - Self-Tapping - Zinc in Clear