Uni-ball Signo RT UM-138 Gel Ink Pen - 0.38 mm - Black

While the 0.38mm tip writes fine lines, I am rather disappointed in the ink reservoir. If you pay close attention, the inner diameter on the refill is much smaller than most normal refillable pens which explains why these pens have such a short lifespan. The inner diameter on this refill is 2mm (approximately 3/32”) whereas other pens, like the Zebra Sarasa or the Uni-ball Signo 0.5mm, have a much wider inner diameter. These pens have a 5mm (approximately 5/32”) inner diameter, resulting in 2.5 times more ink than the Signo 0.38mm RT. It’s a great price, especially for those who love super fine tips. Me? I’ll take the extra ink with a 0.5mm tip.

To the guy who is complaining about the reservoir size. It isn't that the .38 size has a smaller reservoir in particular, it's that the retractable signo's as a model have a smaller reservoir. Any size of signo DX models will have the same size reservoir. If you want .38 and still want a big reservoir go look at the .38 signo DXs. They also come in .28 and .5 btw. Anyways, the pen itself has been good to me as all the models of signo I've tried have been. Other than that sometimes not having to worry about a cap can be a good thing. Also, the grip is farther down the pen, which is better for me because I hold pens closer to the tip, which with the Signo DX model is pretty far up so I end up holding past the grip anyways.

Great retractable pen, the 0.38 line is more like a 0.5 line, which in my opinion is better. As most of the cases, the clip is very fragile, look for the Zebra Sarasa Clip or Pilot Juice, which have a metal mechanism for more versatility in the clip.

Good pen for writing English, Chinese or Japanese. Good control, smooth and even. Good price too.

Really good pen for quick sketching. Very smooth (it occasionally has a few skips, and it will scratch, but its rare). Only real complaint I have is that the ink runs down really quickly, but then again, it is a gel pen.