EFF-ERAYZATM is suitable for: a wide range of non-acid sensitive stones and other hard surfaces, including granite, slate, basalt, brick, ceramic and porcelain tile, terracotta. indoors and outdoor surfaces on floors, walls, facades, showers, masonry and brickwork. Before using please note: EFF-ERAYZATM is acidic / corrosive and will etch and pit acid sensitive surfaces such as marble, limestone, travertine, some concrete / grout products and some metals including aluminium. Do not allow product to come in contact with any non-recommended surface.