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Sheetrock Brand Glass-Mat Liner Panels Mold Tough (UL Type SLX) are 1 in. (25.4 mm) Type X glass-mat liner panels with moisture and mold resistance for use in shaft wall and area separation wall systems. The panels feature a noncombustible, moisture-resistant gypsum core that is encased in a fiberglass mats face and back that shed water. 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 score a 10 (highest). The fiberglass facer is folded around the double-beveled long edges to reinforce and protect the core, and the ends are cut square and even. The panels are UL Classified for fire resistance and can be used in any UL Design in which Type SLX panels are listed.