An amber glass vinegar bottle in the apothecary shape, with a matte black steel pourer.
It is the straight-sided twin of the oil bottle, and having the pair on a counter is what makes the system work — same height, same label, different contents.
Les Flacons de l'Apothicaire assembles its bottles in France and labels them by hand, with a waterproof matte label that survives a wet sink.
Fill it from a bulk refill rather than buying a new plastic bottle. The label is washable, so it can be wiped down as often as the bottle is.