Black Gel Pens Refills, 12 Pack Retractable Gel Ink Pen Refills Bulk, Fine Point 0.5mm Tip Smooth Writing Quick Dry Gel Pen Refills for Journaling Writing School Office Supplies (12 Black)

These are a tiny bit shorter than the pen case I used it in but still worked well. Smooth writing and excellent price. Hate throwing away a whole pen!

Ran out of Muji pen refills and had no nearby store so was looking at alternatives when I came upon these. The measurements matched my Muji pens so I decided to take the risk and buy these. They work pretty well! Too bad the refills are opaque so you can’t see how much is left, but otherwise they fit my knock and cap type Muji pens well and have the same ink quality, smooth writing, and I’ve always been a 0.5 girlie so seems to work for me! Also cheaper than my old refills. Time will tell how long they’ll last in comparison to my previous refills but so far so good!

Very pleased with the quality of these refills. They are an exact fit for my Zenith Zs12 Startraveler pens, and they write just as smoothly, with as fine a line as the originals. Only just started using them, so I don't know about longevity - we'll see, but I'm happy with them.

These are excellent. I appreciate that I do not need to write out the entire pen.

Smooth, dries fast, lasts a while, doesn’t smudge badly if at all, easy to replace