I recommend GSI Creos Mr. Brush Round Fine: http://www.amazon.com/gp/product/B002DTDLRU I used a more expensive art-store brush first, and found this one to have a more even tip with a more reliable stroke. Comfortable grip, too. I just saw they have a super fine, I'll probably order one of those also -- the fine is kind of dicey for doing 1/144 eyes.