TIMCO C2 Deck-Fix Premium Countersunk Green Decking Screws - 4.5 x 50 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. C2 Deck-Fix TX20 CSK GRN 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