USG Sheetrock® Brand Ultra Light Panels Mold Tough® are lightweight 1/2 in. (12.7 mm) gypsum panels that feature proprietary core and paper technologies, resulting in a high strength-to-weight ratio composite design. The noncombustible, moisture-resistant gypsum core is encased in moisture and mold-resistant, 100% recycled green face and brown back papers, and the face paper is folded around the long edges to reinforce and protect the core. When tested in accordance with ASTM D3273, Standard Test Method for Resistance to Growth of Mold on the Surface of Interior Coatings in an Environmental Chamber, the panels meet or exceed ASTM C1396 specifications. The ends of the panels are cut square and even, while the the long edges are tapered, allowing joints to be reinforced and concealed with USG Sheetrock® Brand joint treatment systems.