The Trex Groove Cutter (Router Bit) is designed to work with the Trex Hideaway Hidden Fastening System. Delivering a fast and easy installation process that allows for a clean, fastener-free deck surface. The groove cutter works with Trex Transcend, Trex Enhance, and Trex Select deck boards. Traditional square edge deck boards use standard deck screws and plugs for installation. Using the Trex Groove Cutter precisely grooves the underside of the board to perfectly fit the Trex Hideaway Universal Hidden Fasteners.