The Cortex Fascia Hidden Fastening System is the strongest, easiest way to hide fasteners in Trex Fascia Boards. Cortex for Fascia is engineered for fascia expansion/contraction and plugs are made from Trex fascia board making for a perfect color match. The TORX ttap Drive System is almost impossible to strip-out with the patented stability button that keeps the fastener straight throughout the installation. The Cortex for Fascia is available in a 50 lineal foot complete kit that includes (100) 1-3/4” screws, (105) plugs, (1) counterbore tool and (1) setting tool. The 1-3/4" screws feature a #20 TORX ttap drive system, making it easier to drive tools in a vertical application. The counterbore bit drills an oversized pilot hole for the screw and a hole for the plug, all at the perfect height. The cortex fascia plugs are made from Trex fascia boards. With an exact color and texture match, the system creates a smooth finished look. FastenMaster recommends using (3) fasteners every 18" OC for 12" fascia boards and (2) fasteners every 18" OC for 8" fascia boards. It is recommended to consult the manufacturer installation instructions prior to installation.