PLATINUMCarbon Pen Ink Cartridge - Pack of 4 - Black 2 Set

great service and quality item, thank you

This quick drying ink is waterproof and a great choice for ink and wash watercolor style. I prefer drawing with a fountain pen and this ink is a great match - it fits the terrific value Platinum Preppy fountain pen perfectly making for a highly portable and inexpensive on-the-go combination! You can’t go wrong.

Doesn't fit my Sailor Fude De Mannen - Stroke Style Calligraphy Fountain Pen. Waste of money when description doesn't make sizing clear. Set 2 has a ball in the end. I'd love to know whether these are authentic, as they are supposed to be pigment based and waterfast, and recommended by artists, but I've noticed some reviews saying they bleed. I won't be able to use mine to tell. Very frustrating.

Could just copy+paste my review from Jet Pens, but would rather not.As the title says, this ink works fine with the brush pen I have. So, I would therefore assume for all brush pens as well. It is dark enough for lines (need to cover an area twice for deep black). And considering all brush pens (except the overrated Pentel) come with NON-permanent (can and will wash away) ink, and permanent inks ruin tips usually, this brand of ink is a godsend for all artists who prefer the brush, but also want to be able to draw anywhere (what brush pens are for). I can confirm the cartridges fit just fine into Kuretake pens model 13 and 50 (though 50 has sable bristles, so it's your own risk).

though this refill takes a bit more pressure to install than other refills, it maintains a tight seal and is an economical choice for sketching.

I use this in my platinum fountain pen, which I use for sketching mainly. I have however, used the pen for letter writing as well. The fact that the ink is waterproof is most beneficial for me since I like to use a watercolor wash on my sketches.I think it is a big plus also, knowing that a drop of water will not ruin a letter you spent time composing.This price makes it a great purchase.