DunBong Rollerball Pen Refills, Roller Ball Fine Point 0.5mm, Red Ink Refill Pack of 5 - Replaceable Ballpoint Pen Refills Medium Point (Navy Blue)

It's hard to get too excited about a pen cartridge, but these are great. Smooth and very clean writing.

I've been searching for refills for my Staedtler Premium Rollerball. To the point of trying to match the original part numbers. Found these by measurement, they fit the pen, don't rattle and write a nice flowing line I expect from the Staedtler. Picked up the pen while traveling in Europe for a classic design along with Opinel #7 and #8.

The ink skips and the roller ball scratches against the paper. I tried three cartridges before I threw out the pack. Avoid these refills and the pens that use them. In my case Britto

I needed refills for a few nice pens I have. These work but they're not as smooth as the originals.

I have a bunch of pens I have collected, some of them far more expensive than they should be, these fit even the most expensive ones and write well with them, if you don't feel like shelling out a couple hundred bucks for ink to pens that most people feel uncomfortable walking around with this works great.

First cartridge of four didn’t flow well, trying second cartridge and so far so good

I was looking for refills for some of my favorite writing instruments. These perfectly fitting refills will allow me to continue using my pens for a long time.

Everything was perfect