Self drilling screw with countersunk head and wing tip. For fixing timber to light section steel. Salt spray tested to 1,000 hours. Torx bit in each pack. If you're joining timber to light section steel, these TechFast roofing screws will give you a strong and secure fix. The screws are fitted with breakaway wings to protect the thread from engaging timber while drilling through. The wings ream a hole, then break off when they come into contact with the metal surface being drilled - this engages the thread with the metal, and not the wood.* Self-drilling screw with countersunk head and wing tip* Used for fixing timber to light section steel* No.3 drill tip for self-drilling light gauge steel up to 5mm* Torx-compatible insert for a higher transmission of power* Breakaway wings protect thread when drilling through* Recessed ribs improves countersinking for a flush finish* Salt spray-tested to 1,000 hours* Torx bit included in each pack Forgefix TechFast Light Duty Self Drilling Torx Roof Screw 5.5 x 60mm (100 Pack) in Silver Steel. These Forgefix TechFast Roofing Screws are designed for use in joining timber to steel and for light section purlins. They have a Torx compatible, countersunk head to sit flush to the surface. The self-drilling point enables speedy insertion, and the wings create a clearance hole in the timber to eliminate the chance of 'jacking' when fixing. The screws are zinc plated and have an 'Elementech' coating for superior anti-corrosion, which has been salt spray tested to 1,000 hours. These light section roofing screws are suitable for fixing timber to steel thicknesses of 1.5mm to 4mm. Each pack is supplied with a free Torx compatible bit.The TFCL5560 TechFast Roofing Screws have the following specifications: Size: 5.5 x 60mm.Pack quantity: 100.