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Sheetrock ® Brand UltraLight Sag-Resistant Interior Ceiling Board panels are 12.7 mm (1/2 in.) gypsum panels that feature proprietary core and paper technologies, resulting in a high strength-to-weight ratio composite design. These lightweight panels are also engineered to have superior sag resistance in comparison to traditional 12.7 mm (1/2 in.) gypsum wallboard. The noncombustible gypsum core is encased in 100% recycled face and back papers, and the face paper is folded around the long edges to reinforce and protect the core. 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 CGC Sheetrock ® or Synko ® Brand joint treatment systems.