Sakura Pigma Micron Pen Series XSDK ea.
For size & colour availability see

Pigma Micron Pen Colour and Size Chart here

When accuracy, minute details, and preservation count, the unparalleled archival quality of Pigma Micron pens makes them everyone's first choice.
Artist, writers, and illustrators reach for Pigma Micron and know their work is safeguarded with the permanence of Pigma ink.
The first disposable technical pen using archival pigmented ink, Pigma Micron ink pen is selected for fine-point technical and artistic applications.
Experience smooth, skip-free writing and crisp ink colours that leave consistent lettering and lines every time.
Choose from the range of six nib sizes for precise line widths:
005 = 0.20 mm,
01 = 0.25 mm,
02 = 0.30 mm,
03 = 0.35 mm,
05 = 0.45 mm, and
08 = 0.50 mm.