Diamine Inkvent Fountain Pen Ink 50ml sized glass bottles. Full sized 50ml bottles of writing ink from the fourth Diamine Inkvent Calendar, the Purple Edition. 

Diamine has been manufactured in England since 1864. Their ink is among the finest available; it's safe to use in all brands of fountain pen, even the shimmery ones and the sheening ones (but probably best to give your pen a bit of a rinse after use, just to be on the safe side). All the inks are water-based, acid-free, non-toxic and vegan-friendly. They're superb.

• 50ml
  
• Chameleon shimmer effect
• Water-based
• Non-toxic
• Acid-free
• Vegan-friendly

The only go-to for any brand of fountain pens, especially vintage models.