The Drill-Tec NTB-1HWO is a glass-filled nylon auger fastener with a 1" head. It is designed to secure insulation and single-ply membrane to gypsum, all cementitious wood fiber decks (Permadeck, Insulrock, Tectum, etc.) and certain lightweight concrete decks. The NTB-1HWO may be used with a 3" steel plate for insulation attachment. For single-ply membrane attachment use batten bar.