Classic Decking Screws - PZ - Double Countersunk - Stainless Steel All the features and superior performance of the Classic Multi-Purpose Screw manufactured from A2 Stainless Steel. Offering superior corrosion resistance making it ideal for multiple external applications, especially for the construction of decking platforms. Stainless steel must be used where there is corrosive environment and/or the base material has inherent corrosive characteristics e.g. Green Oak. ? Double countersunk head reduces the likelihood of head shear and assists completion of countersinking ? Helix shank for removing debris and to improve clamping ? Single slash point to reduce torque and the risk of timber splitting at low edge distance.