M-Glass Exterior Sheathing is a high performance mold and moisture resistant panel designed for direct attachment to exterior side-wall and soffit framing as a underlayment for various exterior materials such as wood, metal or vinyl siding, properly detailed Exterior Insulation Finish Systems (EIFS), masonry veneer, stucco, shingles, etc. It is produced in 1/2” and 5/8” thicknesses with the 5/8” M-Glass Exterior Sheathing having a UL classified formulated Type X core for use in approved fire rated assemblies. American Gypsum products contain no asbestos and no detectable levels of formaldehyde.