Royal & Langnickel Nano-Liner Drawing Pen, Black, 4-Pack Model RD701 is a carded 4 -piece Nano-Liner pen set, black ink, sizes 01, 02, 03, 05 (point sizes 0.1, 0.2, 0.3 and 0.5mm) High-tech nib assures smooth action and even ink flow Metal nib collar adds strength, allows use with straight edges, templates and other tools