Used for stitching metal or attaching to metal. A pre-drilled hole is required. Manufactured from A2 Stainless Steel for use where ultimate corrosion resistance. Stainless steel must be used where there is corrosive environment and/or the base material has inherent corrosive characteristics. Countersunk head gives a discreet finish into pre-countersunk holes Stainless Steel suitable for outdoor applications 60 self-tapping thread for ease of insertion" Gauge: 8 Length inch: 5/8 Thread Dia. mm: 4.2 Length mm: 16 Head Type: Countersunk Recess Type: Pozi Point Type: AB Point Driver Bit Size: PZ2 Material: Austenitic Stainless Steel (A2-304)Size 4.2 x 16 - 200 Pieces Timco Metal Tapping Screws - PZ - Countersunk - Self-Tapping - A2 Stainless in Silver