5/8' ToughRock® Fireguard X® Gypsum Sheathing is recommended for use in new building construction or renovation work that is covered by an exterior finish cladding such as vinyl/fiber cement siding, masonry veneer or wire lath stucco. It is designed for direct mechanical attachment to wood or steel framing. 5/8' ToughRock Fireguard X Sheathing is UL and ULC classified Type X for use in a variety of fire-rated assemblies. ToughRock Sheathing is manufactured to meet the requirements of ASTM C1396, Section 9, and CSA-A82.27-M and Federal Specification SS-L-30D, Type II, Grade W, X and should be installed per ASTM C1280 and Gypsum Association documents GA-253 and GA-254.