 Introducing Monovert A Color Changing Ink. Offered in 9 beautiful colors, the color changing ink is ready to show its secrets using the special changer liquid. Use any of the 9 color changing inks via fountain pen or brush. Fill the clean fountain pen or use a q-tip to apply the changer. Then watch the transformation happen. So many colors and numerous possibilities. Make every stroke a work of art with Monovert A Color Changing Ink Collection.