This is Kaweco Pearl Black ink that I used in the Kaweco Chess Sport pen when I tested it. You can find the Chess Sport pen review Here I used a Pearl Black cartridge in the Chess Sport and it was fitted with a gold plated steel M nib. I also switched in a 1.1 steel nib as a comparison. Both nibs wrote really smoothly with Pearl Black ink. Even though I'm not a fan of black inks, I actually enjoyed writing with this one. Pearl Black is a quite saturated dark black ink. It's the blackest black ink that I have tried. It doesn't lean grey or greenish. It is a really well behaved ink and I can highly recommend it as a top quality ink. You might still find some older bottles of Kaweco black ink. The two inks are a very similar colour. However, you can tell if you have one of the newer bottles or packs of cartridges because the name of the ink is now printed on the boxes. Kaweco cartridges are also now impressed with their brand name. This ink isn't waterproof, and it doesn't stain fingers. Kaweco ink is made in Germany. It is available in 30ml bottles or packs containing 6 standard international sized cartridges.