The Sakura Pigma Micron pen is an outstanding drawing tool. Available in multiple line widths, I personally use the 01 (0.25mm) and 05 (0.45mm) in my sketchbooks. I also have the fine tipped brush pen for more expressive line-work. All the Microns use a pigmented ink that is chemically stable and is both waterproof and lightfast. The pens aren’t refillable (worn out pens can be brought to Staples for recycling), though it’s easy enough to twist off the barrel cap and refill the reservoir with an ink of your own choosing.
A real concern with fineliner pens is the durability of the nibs, with some brands wearing down quicker than others. I find that the Microns are very good in this respect, though keep in mind, choice of paper will also affect the nib’s lifespan. A sheet with a bond or smooth vellum surface will be far less abrasive than a textured sheet of Manilla or Kraft.
I bring these Microns into the field when I’m sketching, and as a consequence, they get tossed in my backpack or shoved into pockets. Over time, the sound of the ink reservoir rattling around inside the handle can be heard, but not to worry...it doesn’t impede the ink flow.
One suggestion I have for making the Micron pen even better, would be to manufacture them from recycled plastics or plastic alternatives that utilize corn. I’ve purchased baby toys and travel luggage made from recycled bottles and milk jugs, so it’s definitely possible to move away from petrochemicals.
Apart from being made of plastic, this pen is very welcome in my studio. I find it reassuring to know that the drawings made today will not fade away, and likely will be around long after I’m gone.
Here’s a link to the Sakura website for those interested in learning more: Pigma Micron
ps. You might also like to try this brush pen: Pentel Pocket Brush Review