KWZ Iron Gall Turquoise fountain pen ink.
KWZ inks are handmade in Poland and each glass bottle contains 60 mL of handmade fountain pen ink.
See the entire collection of KWZ inks available from Lemur Ink.
Although many users have had no issues with KWZ Iron Gall inks and they have been known to operate completely fine in modern fountain pens (including those with stainless steel nibs), we still urge caution and recommend regular use of the pen, as well as practicing good pen hygiene.
Read KWZ's blog about using their iron gall ink in modern fountain pens.