FlexWrap NF is designed to help protect vulnerable corners against air and water intrusion, as part of a complete DuPont Building Envelope Solution. FlexWrap NF is effective across a range of window and door designs and a wide range of typical wall substrates, gypsum, including OSB, plywood, concrete masonry unit (CMU) and other non-nailable sheathing materials. The "NF" in DuPont FlexWrap NF means "no fasteners." Instead, DuPont FlexWrap NF is a self adhered, extendable flashing backed with a 100% butyl-based adhesive layer, making one-step installation - and protection - possible. And because it's an extendible flashing material, DuPont FlexWrap NF can be stretched and wrapped into a rough window opening before the window is installed, or flashed around arched or custom-shaped windows, as well as other wall penetrations.