BTS Bangtan Boys Theme Gel Pen Attached for Kids, Birthday Return Gifts, Creative Stationery Student School Supply, Gifting Or Collectible (Diary Attached). 1Pc Smooth Gel Ink: The pen uses gel ink, which provides a smooth and effortless writing experience. The ink flows evenly, reducing the risk of smudging or skipping while writing or drawing. Material: Refillable, resilient, soft PVC. High-quality pen: approximately 6 inches long, 0.5 mm round tip; round ink flows uniformly; sharp and noticeable lines; smooth, accurate writing.