Permanent: Quick drying and permanent! Tile grout pens: Get one, two, four or eight tile grout revival pens! Formula: Water based, non-toxic and with a low odour. Easy to use: Simply draw along discoloured grout to colour it white. Resistant to: Water and mould. Perfect for: Making your tiled wall look fresh and clean. | Tile Grout Revival Pen | Wowcher