Marketed as the "World's Thinnest Pen", I was anxious to give the Uni-Ball Signo Bit 0.18mm pen a whirl, and I was pleasantly surprised. I didn't have very high hopes after using the 0.38mm version of this pen - it is fine, but tends to clog easily, causing me to stop and start frequently - but the 0.18mm version seemed to not clog as much. This model is delicate, as you can imagine, but if you just watch the pace you are writing or drawing at, I think you will like it.