The fiberglass face of USG's Sheetrock Glass-Mat Mold Tough Abuse-Resistant Firecode X Gypsum Drywall Panels are folded around the long edges to reinforce and protect the core, and the ends are cut square and even. The long edges of the panels are tapered, allowing joints to be reinforced and concealed with Sheetrock® Brand joint treatment systems. The panels are UL Classified for fire resistance and can be used in any UL Design in which Type AR panels are listed.