Absolutely and totally loving these Tombow Fudenosuke Brush Pens from Jetpens. This was the first piece I did with one and I was hooked from the word "go."
I've been a huge fan of brush pens for a while, having about 45 different colors of the Pitt brush pens in my possession - but though they are quite wonderful in a number of different applications, they do not really allow for super fine lines and as I prefer to work small, they don't always suit my needs.
The Tombow Fudenosukes have a very short hard brush that allow me to do some incredible line variations and at $2.25 each, I am ALWAYS going to want to have a few of these on hand.
Product details on the Tombow Fudenosuke Brush Pens from the Jetpens site:
"The special elastomer pen tip of the Fudensoke line gives artists and calligraphers the ability to control strokes with precision. The pens are ideal for writing kanji (Chinese characters). Barrels are made of recycled polypropylene plastic. These non-refillable brushes are available in hard, soft and dual color (black and gray) brush tips"
Of note - the ink in these pens is not waterproof and the only other limitation I found is that these pens are better for short lines rather than drawing across an entire page.