The green-black UM-151...
December 7, 2014
The green-black UM-151 is the pen I use every day at work and home, and I have
several. The ink color is conservative enough for work but a nice change from
black, blue, or blue-black, and the ink is smooth, waterproof, and provided in a
extremely generous quantity (lasts months for me).
(Minor) issues noted over a year of use:
1) Occasional skipping with one particular pen, but a firm tap on the paper
corrected this easily.
2) The ink dried slowly on a postcard made of some kind of slick coated paper.
It works great on all other papers I've used, though.