Forgefix TechFast Composite Panels to Steel Hex Screws with 16mm EPDM washers, are used to join composite panels to steel frame buildings. They have a specially designed compression control thread to prevent damage and denting of panels. They are fire 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 Composite Panels to Steel Hex Screws have the following specification: Size: 5.5 x 115mm Insulation Thickness: 49-94mm Pack Size: 100 Drill Tip: No.3 No.3 drill tip for self-drilling in light gauge steel up to 5mm.