While the cartridges are not usable, a syringe can be employed. It is somewhat flexible, with an easy opening/closing mechanism, is easy to fill, and has a grip that is not ideal. The writing quality is good (the nib glides smoothly). The cap appears to seal well against water.

Very nice.

This is a standard 0.7 pen. I don't perceive it as having a parallel nib. It writes with a slightly rougher feel on paper, but it's not a significant issue.

This is a positive product description. The writing quality is good. The ink flows consistently without problems. A standard French ink cartridge does not fit. The included cartridge is refillable.