Gold Bond BRAND XP Fire-Rated 5/16-inch Radius Wall is for radius applications requiring fire-rated assemblies. The product is used in double-layered construction. A one-hour UL tested assembly can be achieved with two layers, and a two-hour UL tested assembly can be achieved with four layers. The special PURPLE XP paper protects against mold, mildew and moisture, and is also abrasion-resistant. Combined with a denser core, XP Fire-Rated Radius Wall provides greater resistance to surface abuse when tested. For more information, visit nationalgypsum.com.