Tech Fast-Hex-Head-Stitching-Screw-Self-Drill-6-3-x-22mm-Pack-100-Forge Fix-TFHS6322-p-The-Forgefix-Hex-Head-Stitching-Screws-are-designed-specifically-for-joining-cladding-sheets-together-They-have-a-Hex-head-&-a-self-drilling-point-which-enables-speedy-insertion-The-rubber-washer-beneath-the-aluminium-flange-expands-under-pressure-to-form-a-permanent-weather-seal-p-p-The-screws-are-zinc-plated-&-have-an-Elementech-coating-for-superior-corrosion-resistance-which-is-spray-tested