Self drilling screw with hex / flange head and EPDM washers. For fixing light section purlins. Salt spray tested to 1,000 hours. Perfect for light-duty sheet to steel fixings, these TechFast roofing screws are self-drilling with a hex/flange head and 16mm rubber washers. The washers expand under pressure to form a permanent weather seal. Roofing screws for fixing sheets to steel. Self-drilling screws with hex/flange head and EPDM washers. No.3 drill tip for self-drilling in light gauge steel up to 5mm. 16mm rubber washer creates a permanent weather seal. Elementech corrosion-resistant coating for durability. Salt spray-tested to 1,000 hours. TechFast Hex/Washer Self Drilling Roof Screw 5.5 x 100mm (100 Pack) in Silver Rubber/Steel. These Forgefix TechFast Roofing Sheets to Steel Hex Screws are used for joining metal roofing panels to steel frame buildings. The screws are fire resistant and corrosion resistant. Protected by Elementech corrosion resistant coating, salt spray tested to 1000 hours. Complies with EU Safety, Health and Environmental requirements. They are supplied with 16mm EPDM rubber washers. These Forgefix TechFast Roofing Sheets to Steel Hex Screws have the following specification: Size: 5.5 x 100mm Effective Thread Length: 83mm Pack Size: 100 Drill Tip: No.3 No.3 drill tip for self-drilling in heavy gauge steel up to 5mm.