As per my experience, Pilot V5 Pen Liquid Ink Roller Ball Pens are not cartridge filling pen like original V7. These are use and throw and I am really disappointed. Too much ink was spread on my paper while writing with this pen. The moment I stopped for a second while writing, I saw a big spread ink circle where I stopped. It is a fake product. I realized when I opened its packet and even after replacement, it ended with same result.