Sakura Gelly Roll Moonlight Pen, Fine, Cool Gray. This Gelly Roll Moonlight Pen sheds light onto art works, school projects, memos and more. The ultra vivid, opaque ink is luminous on light or dark paper and on most porous surfaces. The ink flows through a rollerball with creamy smooth consistency resulting in extraordinary writing comfort. The fluorescent color glows vibrantly under a black light for extra pop!