The Uni Jetstream 101 Pen features a tungsten carbide ball nib for smooth and consistent writing. The ink is acid-free and dries fast so you can enjoy writing without smudges and smears. • It produces a 0.7 mm line width for everyday writing. • It's suitable for use on paper, card and more. • The ink dries quickly to prevent smudges and smears. • The crisp dense lines will be sure to stand out on your page. • The ink is acid-free for added peace of mind. • The ink in this pen is red.