This Schluter Kerdi Board 12" x 20" Shower Niche is a prefabricated shower niche made of Schluter Kerdi Board. Lightweight for ease of installation. Waterproof niche once installed is ready for tiling. Can be installed in both Schluter-Kerdi and Schluter-Kerdi-Board wall assemblies. Features a 1/2 in. thick x 2 in. wide integrated bonding flange. Features a prefabricated Kerdi-Board shelf that can be installed at any height to create separate compartments within the shower niche if desired. Measures 12 in. x 20 in., with a 3-1/2 in. depth. California residents see Prop 65 WARNINGS. Warning: This product can expose you to chemicals which is [are] known to the State of California to cause cancer and birth defects or other reproductive harm.