Halo® is The Advanced Rigid Insulation Envelope: it's the insulating system perfectly designed for specific applications. Halo is powered by Neopor® GPS (Graphite Polystyrene) by BASF®: the new standard in thermal insulation. Halo's GPS foam core offers best-in-class R-value and is Green Guard® Certified for superior indoor air quality. Halo® Exterra® is perfectly designed for Exterior Applications. We call it the "Advanced Exterior Insulating Sheathing". Halo Exterra is breathable (up to a thickness of 1.5") to help exterior walls stay dry and healthy. Plus, Halo Exterra offers a built-in weather barrier (When taped) that can save you up to $12 per sheet of Exterra by eliminating the need to buy and install a separate weather barrier.