Tackles hard to clean stains in the bath, kitchen, garage, and outdoors. Cleans ceramic tile, porcelain, masonry, concrete, and other hard surfaces removing deep stains caused by hard water lime scale, rust, and burnt foods. Use on porcelain sinks, tubs, and shower tile. Clean outdoor water features, pool, and spa. Great for cleaning grills, grates and porcelain barbecues. Stone size: 5.25 x 1.25 x .75 .