Koi Coloring Brush
A PMD favorite! These pens are very very similar to Tombow Dual Brush Pens. They work GREAT for watercolor and I would say, even more so than Tombow's, they are EXTREMELY "juicy" with ink. I always feel like this helps to combat the worrisome 'frayed' tip that a lot of us experience.
You'll notice in the section of the video where I show that it is water-soluble and a good option for watercoloring that this black marker actually gives off a greenish/blue hue when used with water. There are few other pens you'll see in the rest of the videos that give a more solid black ink watercolor effect than this pen.
