The Cortex for Fascia Hidden Fastening System is the fastest, easiest way to hide fasteners in composite, capstock, and PVC fascia boards. Cortex offers a strong connection between the fascia board and joist while also concealing fasteners across the entire deck. Just set the screws in place and the setting tool makes sure you hit the perfect depth every time. After the screw is installed just place the provided plugs in place and hammer down. You now have a securely fastened deck without any of the unsightly fasteners!