SLX Sheathing is an extruded polystyrene (XPS) board that gives you an edge on moisture resistance and thermal performance. With an R-Value of 5.0 per inch of thickness, it is an ideal thermal insulator that increases a home's energy efficiency. And because it's made of XPS, the board has high water resistance, allowing it to retain its insulating properties over time. SLX has interlocking shiplap edges that reduce energy-robbing seams and gaps, while also providing an extra barrier against moisture infiltration. Tough film facers on both sides of the board produce greater durability and less waste.