Techfast Roofing Sheets To Steel. Used For Joining Metal Roofing Panels To Steel Frame Buildings. No Washer. 8Mm Hex Head. No.3 Drill Tip For Self-Drilling In Light Gauge Steel Up To 5Mm. Fire And Corrosion Resistant, Protected By Elementech Corrosion Resistant Coating, Salt Spray Tested To 1000 Hours. Complies With Eu Safety, Health And Environmental Requirements.