C2 Advanced Decking Timber Screws - TX - Countersunk - Exterior - Green THESE SCREW ARE TORX HEAD - TX20 A premium decking screw using the C2 twin-cut technology. Coated with a patented multi-layer corrosion resistant plating to withstand up to 1,000 hours in a salt spray cabinet. This new and innovative design enables the screw to rapidly penetrate the timber, cleanly countersink and securely clamp the decking board to the joists. • Strengthened head to prevent shearing when installed with an impact tool • Ribs under the head for improved countersinking • Helix shank for removing debris and to improve clamping • Coated with a patented multi-layer corrosion resistant plating to withstand 1,000 hours salt spray • Patented twin cut technology for rapid "pick-up" and reduces timber splitting.