The unique gel ink of the blue Madam Sew Fabric Pen makes clear and accurate marks on fabrics and disappears after ironing. It is truly Amazing to see! And a real game changer because you don’t have to wash it out or worry that it will fade before you are finished with your project. Our fabric marking pen has a small, accurate writing point that leaves a thin yet nicely visible line and works extraordinarily well on nearly all fabrics. So what you get is a thin, accurate and clearly visible mark that stays visible for as long as you want it and is removed with an easy pass of a hot iron. A must-have for all sewists and quilters! If you love this one pen, we also carry a four-color, multi-pack of Heat Erasable Marking Pen.