DD Fasteners D-tough series Screw (a.k.a Replace Marutex tek screw) is used for metal to metal fixing of thick steel purlin and hot rolled steel. Used for metal to metal fixing in the HAVAC, plumbing and steel fabrication industries where thick steel section is in use. A general all purpose metal to thick metal fixing product with a drill capacity of up to 12mm. Features & Benefits Versatile all purpose fastener for fixing into thick steel Drilling point for fast and easy application into steel up to 12mm thick High pull-out strength Ruspert Coating( S.S.T 1500 hours) corrosion protection available Deep Drilling screws with a long extended Self-Drilling point to drill into thicker metal. The Hex head allows for high torque transfer when drilling up to 12mm thickness.   Imperial: Dia 12G to 14G & Lengths 32mm - 300mm Thread: Series 500 Fine Thread Head Style: 3/8" and 5/16" Hex Heads, No Neoprene washer Material/Finish: Zinc Yellow, Class 3/ 4, Stainless Steel Pitch: 20-24 Shorter screws - 32-70 mm suitable for drilling into steel cladding, roofing, fixtures, and frames into metal 1.2-5.0 mm Longer screws - 75-300mm are suitable for drilling into composite panels & other thick insulating cladding to steel purlins & sections 3.0-12.0mm Website : Stay tuned Cheers