Tombow Fudenosuke Brush Pen GCD-121 82040, Twin Tip, Fine, Black and Grey Ink. Fudenosuke Firm Tip Brush Pen features a firm yet flexible brush tip for different writing and drawing techniques. Create extra-fine, fine or medium strokes by a change in brush pressure. Great for calligraphy and art drawings. Barrels are made of recycled polypropylene plastic. Twin tip – water-based, pigmented black and grey ink. Fine line. Odorless. Non-refillable.