天然草筆芯，黑色墨水

The black ink flows smoothly and doesn't skip, even when I'm writing fast during meetings. Popped the refill in and my pen writes like it's brand new again.

Dropped this black refill into my pen and it writes just as smoothly as the original did. Glad I don't have to toss the whole pen now — the ink flows evenly with no skipping.

The black ink flows smooth and doesn't skip, which is what I was hoping for. Only gripe is that it ran dry a bit sooner than my last one, but it's an easy fix since the refills are simple to pop in.