I'm not sure about the problems to which the other reviewers are referring. I have the purple in my Waterman Liaison rollerball, and it works great. I'm wondering if maybe it fits better as a rollerball replacement then for one of Waterman's ballpoints? I haven't tried it in any ballpoints. The Liaison is a pretty large pen, so that might be why it works as well. Maybe people could add comments which Waterman styles didn't work for them?I've had the refill in there for a while. I hadn't used my pen in several months, and the refill started right back up no problem when I started using it again and hasn't dried out since then.I think it writes very smoothly. It's sort of a ballpoint/rollerball hybrid. Overall I'm very satisfied.