Okay for the price
I've filled 3 so far and on 2 of them, the brush piece doesn't push all the way down into the pen but it doesn't seem like it's going to leak. Judging on the quality, these probably shouldn't be refilled. I wish the brush could hold more oil, you either barely get any or too much, there is no in-between. All in all, they're okay and they serve their purpose but after I use these up, I'd look for pens of better quality that I can refill to minimize waste.
Rating: 3 stars