I purchased these to replace the cartridges in my Kuretake No. 8 pen. These refill cartridges are great. The ink is a nice solid black, and flows
through the pen wonderfully. It's just wet enough and dries fairly quickly which
is always a plus since I'm one to forget to ink so my hand doesn't smear any of
the already put down lines. This one has very minimum smearing if I mess up
thankfully. Waterproof, and alcohol marker proof. Wonderful ink cartridges and perfect for
the Kuretake No. 8.