Tile Grout Pen, Waterproof And Mildew-Resistant, For Creating A Neat And Tidy Home Space. It Can Protect The Gaps Between Tiles, Making Them Look As Good As New. It Can Be Exposed To Water For Up To 60 Minutes, Providing Waterproof, Stain-Resistant And Non-Fading Protection. The Usage Is Simple: Clean And Dry The Base Surface, Draw Along The Gaps Before The Ink Dries, Do Not Get It Wet, And Let It Dry For About 1 Hour. It Can Ensure Long-Lasting Results.