Decking Screw Pozi Compatible ST Green Anti-Corrosion 4.5 x 50mm Tub 1000 - ForgeFix DS4550T, These Forgefix single threaded Decking Screws have Pozi compatible heads and are specially designed, hardened and green treated. The design of the screw helps prevent splitting the boards, and allowing them to expand and contract with the changing seasons. APPLICATIONSpecifically used in Decking applications but also widely used in exterior timber and fencing applications. The 1,000 hour green treated finish offers excellent corrosion resistance to ACQ (Alkaline Copper Quaternary) treated timber used in construction and decking applications. The Pozidriv screw is similar in appearance to the classic Phillips cross-head, but in fact is very different. The Pozidriv has four additional points of contact, and does not have the rounded corners that the Phillips screw drive has. The biggest advantage it offers is that, when used with the correct tooling in good condition, it does not cam out, all