There are 3 pens available, as pictured below.

a 0.2 mm nib with black ink,
a 0.1 mm nib with black ink, and
a 0.1 mm nib with sepia ink.

The pens are not refillable. The nibs are unmarked, appear to be made of steel, and are reasonably smooth. Unsurprisingly, I found the F02 nib to be a bit smoother than the F01s. Both are firm approaching state of nail – they appeared to yield to some amount of pressure, but did not yield any significant line variation in use. They put down a decent wet line with good flow, though the F01s wrote a bit dry when I first uncapped them and needed a gentle shake or two. (Incidentally, the barrel of the pen advises you to not “shake hard and drop,” as “ink may leak.” Thanks.)

I sometimes draw a bit and have also been known to put a splash of watercolor on those drawings when “finished.” The Multiliners are great for ink and wash drawings, completely waterproof. Well, the barrels of the Drawing Pens say “Copic-proof” (how recursive,) but, ominously, NOT “waterproof.”

Below are the results of dragging a Niji waterbrush across some doodles. This was done maybe 20 minutes after the “drawings” were finished.

As you can see, smearing (along with its old friend beading – these were done in that hipster paragon the Moleskine sketchbook) occurred. If you’re buying these to use with Copic markers, you’re, well, Copic-cetic. If not, expect smearing and tears (yours, not the pens, which as we all know are inanimate objects incapable of tears.) I’m somewhat confused as to why Copic introduced these, as they already produce a pretty extensive line of drawing pens and markers. My only surmise is that these are meant to compete with the Tachikawa line of disposable Manga pens. These are a reasonably decent, inexpensive fountain pen, and probably a step up from a Preppy or a Varsity.