Moisture-Resistant, Cement-Based, Rapid-Drying, Smoothing and Finishing Compound provides a smooth finish on a variety of substrates in interior areas. A true high-performance featheredge up to 1″. Does not require priming, unless over gypsum. Over gypsum, preferably, use Schönox AST with Schönox AP and APF synthetic gypsum self-levelers.