Ohto 0.7mm Black Oil-based Ink Refill (R-4C7NP), for Ohto Multi-function Ballpoint Pen, MULTI-Smart 4, × 6 Packs/total 6 pcs (Japan Import) [Komainu-Dou Original Package]

Contain a lot of ink and work well until entirely empty! worked well and did not dry out over a 5 year period of regular use.

For those that looking for ink cartridges for bamboo folio pens; This does fit the pen but it does not work like the original cartridges. The input is read but it comes out, in the app, squiggly and like you don't lift up the pen; so imagine writing something without ever lifting up the pen. Apart from that the cartridges are great if you happen to have pens that use these cartridges.

There are various sizes of refills out there and multiple options with each size. It's worth one's time to find a favorite option for the refill sizes one uses.For the D1 size, I've settled on this one as my favorite, the Ohto 0.7mm black. The oil-based ink writes reliably on a variety of surfaces and it is a very smooth experience. I'm left-handed and we have to push the tip of a pen across the paper instead of dragging it like right-handers so smoothness is important. Then I prefer fine point and the 0.7mm ballpoint puts out a line that fits the bill.One neat thing about this refill is the tip. Instead of the typical conical point it has more of a needle tip. It almost looks like the tip on a mechanical pencil yet it's a pen. I think aesthetically that's pretty cool.

These ink refills are great quality and arrived very quickly. I immediately refilled my Ohto multi when I received these, I wanted to be sure these would work and were up to expectations - as the ink that comes with the multi is usually great quality but I happened to receive a streaky very inconsistent refill from another vendor recently and could barely write a small note… these were perfect and all concerns gone.

Smooth writing. And easy to install.I recommend the ink refills.

were not the right length

Three of the 5 refills I got weren't the right size.

Highly recommended for any D1 ink replacement. Slim lines and it seems to last for a reasonably long time.The only issue I have is that sometimes, if the pen isn’t used in a while, you might need to run it across a scrap sheet to get the ink running again.Highly recommend