YEHAM&reg;Disappearing Ink Vanishing Air Erasable Pen(9 PACK,3 COLOR) This water-soluble disappearing ink keeps your marks visible only while you need to see them Time to disappear: 1-7 days disappear automatically. Pink pen - 1 to 7 days automatically fade or use water to wipe them off immediately. Purple pen - 2 to 14 days automatically fade or use water to wipe them off immediately. Blue pen - use water to wipe them off immediately. Water erasable pen can write on fabric surface, and is especially used for 11CT/14CT cross stitch, handicraft, needlework, etc for temporary marking. This fabric marker is handy for temporary marking of pattern instructions or designs on fabric, which can then be removed by dipping in water. Fabric marker pen used for dressmaking, crafts, quilting, embroidery and temporary line markings. Ink is erasable easily and quickly by water, making great convenience for your projects.