The Cortex Hidden Fastening System is the fastest, easiest way to hide the heads of your deck screws on market-leading deck board types. Set the screw, set the plug, and you"re all set. Cortex offers a strong connection between the deck board and the joist and can hide fasteners across the entire deck: first and last board, perimeter, and stairs. Cortex is available for use in the following AZEK decking brands: AZEK®: Arbor, Terra and Harvest Collection All screws, plugs, and setting tools are included in every box.