Zebra 0.4mm Blue Ink Refill (JF-0.4), for Zebra Sarasa Clip 0.4 Gel Ballpoint Pen(JJS15-BL), × 5 Pack/total 5 pcs (Japan Import) [Komainu-Dou Original Package]

It's very slick and super fine, compares to Uniball 0.38 gel or 0.5 ballpoint.

The best writing pen out there.

It fits the TUL pen, for which TUL doesn't sell refills, perfectly. You just need to re-use the spring that came with your TUL pen TUL Retractable Gel Pens 0.5 mm Fine Point, Blue 12/pk. So don't throw away the old ink cartridge until you get the replacement loaded and have re-used the spring. 1. Unscrew the bottom silver tip. 2. Remove the old cartridge. 3. Remove the spring from the old cartridge. 4. Transfer spring to the new cartridge. 5. Load cartridge with spring into the pen. 6. Screw the bottom silver tip back on.Note the same series of refills fits the same series of TUL pens.

I have ordered several refills for my refillable pen, but they have been sporadic as to whether or not they work. When I received these, they worked great. I like the line (the more narrow lines) and I can tell that I will get to use all the ink from each refill so this should last me a while.

Not much to say, these work really well and I'm happy to be able to reduce waste and keep using my favorite pens.

Really enjoy the writing of these refills and the sarsa clip pen. The color is more of a blue black vs a true blue and still writes very smooth. There was one refill cartridge that I received that was actually black vs blue. Checked the number on the side of the cartridge and it was correct. Thinking something was mistaken during manufacturing. Not a big deal. It takes quite a while to go through one ink cartridge and I use a pen for writing everyday. Blue (Blue Black) ink number = 1608. Black ink number is 1605.

Fit perfectly and a great feel. Wish they came in purple, but they are good quality and definitely get the job done.

Not sure what sheerness means. But they are sheer. The ink skips and isnt like a nice solid blue like the original ink in the pens. I wont buy this again.