Forge Fix-Tec-Fix-Phillips-Roofing-Screw-Timber-Steel-Heavy-Section-Forge Fix-TSLS4838U-These-Forgefix-Tec-Fix-Roofing-Screws-are-self-drilling-winged-&-have-countersunk-heads-Suitable-for-use-when-fixing-timber-to-light-section-steel-thickness-from-1-5mm-to-4-0mm-Self-drilling-screws-have-a-drill-shaped-point-to-cut-through-the-substrate-to-eliminate-the-need-for-drilling-a-pilot-hole-They-are-designed-for-use-in-soft-steel-or-other-metals-The-Phillips-screw-has-four-simple-tapered-s