Available here are Clutch Head Countersunk Security Self Tapping Screws. The clutch head is the original one-way security drive. The special ridged design of this drive means that it can only operate in a clockwise motion. Installed using standard slotted screwdriver - no specialist tools required. These are Case Hardened Steel with a Zinc Plated (CR-3) Finish. We do also stock this item in A2 Stainless Steel. This item is sold in a box quantity of 100. This is not a stock item therefore please allow 3-5 working days for dispatch. As this is not kept as a stock item, this is non-returnable. Click Here to view installation video. No.12 x 3" Clutch Head CSK Security Woodscrew - Zinc Plated - Box of 200