Small brass stoppers, to be applied to partially used ink cartridges, for using them again later.
Who doesn't like to frequently change the ink color? In case of cartridge-filled fountain pens it's quite complicated, with a big waste of ink and, in the long run, money.
Using these small caps you can just pull out the cartridge, seal it with the stopper and set it aside for later use.
The stoppers are machined from OT 58 brass which has no reaction with ink. Made in Italy.
Suitable for International Standard size ink cartridges.