The Tombow Fudenosuke Double-Sided brush pen features dual firm but flexible elastomer brush tips. Its dual brush tips have one in black ink and one in grey ink. Its firm tips work beautifully for different lettering and drawing techniques. Great for calligraphy and art drawings. Artists and calligraphers can create extra-fine, fine or medium strokes by changing brush pressure. The barrel is made of recycled polypropylene plastic material. Its pigment ink is water-based and odorless.