The Gelly Roll Moonlight 12 has a line width of 0.5 mm. The Gelly Roll pens compose without a hitch and have a steady progression of ink. The pen is great for drawing, lettering, journaling, enriching and composing. Evening glow is the main really splendid gel pen. Ideal for use on hued, white and dark paper. The fluorescent tones shine magnificently on dark paper and under dark light. Substance might differ.