Winsor & Newton twin-tipped Neon Markers offer brilliant fluorescent colour in high quality water-based ink. Each pen features a? a broader bullet nib suitable for filling in large areas and a smaller one for detailed work.??The translucent inks are easy to blend and overlay and the nibs give you consistent coverage with no streaks. Fine tip produces approximately 1-2mm line; medium tip approximately 3-4mm depending on angle and pressure applied. The inks are fluorescent lightfast and glow under UV light.