The Polymer GypTec is designed to thread into the substrate but should not penetrate the deck. An internal 1/4" square (driver bit included) assures fast and easy installation. The fastener features a wide buttress thread design for excellent pull-out resistance, and tabs that lock the plate to the head of the fastener. The Polymer GypTec is used with 3" steel plates for insulation and 2" steel plates for membrane attachment. It is a glass-filled nylon auger fastener with 1" head designed to secure insulation and single-ply membrane to gypsum and cementitious wood fiber (i.e., Insulrock, Permadeck, Tectum, etc.).