Specifically designed to attach composite panel to light section steel (Max. 5mm). Self-drilling point with hexagon head and split thread. Exterior plating gives a reliable and durable corrosion resistant coating which resists 500 hours salt spray" Thread Dia. mm: 5.5: 6.3 Length mm: 115 Head Type: Hex Fixed Washer Dia. mm: 12.00 Point Type: Self-Drilling No.3 Socket Size mm: 8 Finish: Exterior (Silver Organic) Material: Case & Core Hardened Carbon Steel Effective Thread Length mm: 41 Max Drilling Thickness mm: 5.0Size 5.5/6.3 x 115 - 100 pcs Timco Metal Composite Panel Screws - Hex - EPDM Washer - Self-Drilling in Silver