Ideally suited to refresh and lighten the colours of unsightly grout lines. Since the marker's ink is waterproof, grout lines in a bathroom can also be treated. The grout lines are water-resistant within a very short time. Thanks to the high opacity of the ink, all old grout lines in sanitary areas will look new again. The grout marker comes with 3 spare nibs for a long service life. High-quality brand product.