Gelly Roll Moonlight Pens shed light onto art works, school projects, memos and more. Ultra vivid, opaque inks are luminous on light or dark paper and on most porous surfaces. The ink flows through a medium or fine-nib rollerball with creamy smooth consistency resulting in extraordinary writing comfort. These truly fluorescent colors glow under a black light. These pens are suitable for almost any permanent writing application and are waterproof, too.