Regardless of what material you like, the most striking feature of these pens is the middle area where it's obvious that something unconventional is happening. You can see two separate cavities right in the middle, which is the first indication that this pen is not your normal fountain pen. On closer inspection, you'll see that there are also two caps. And with that comes two separate nibs and feed systems. Essentially, this pen is two eyedropper pens connected back to back and divided by a small wall in the middle to keep the ink reservoirs separated.
I really love how everything about this pen is perfectly balanced. Each side of the pen is exactly 50% of the overall size. The caps are the same size, the ink reservoirs are the same size, the nibs are the same size, and the grip sections are also identical. The only difference between the two ends is the nib tip size. One side is fine while the other is medium.
Filling the pens is really simple. They use an eyedropper filling system, so you just unscrew one of the grip sections, fill the reservoir with ink, and replace the section. Repeat on the other side! There are o-rings on the end of the section to keep any ink from seeping out over time, and the fit and finish is really tight and well done. I have no concerns over either end leaking.