A Luggin-capillary is a special tube, which highly matters at measurements under current flow. When measuring a voltage, it occurs, related to the distance to the working-electrode, a drop of the voltage. Keeping a short distance, the reference electrode is linked to the electrolytes via the Luggin-capillary.
The specific application of the customer dealed with the electrochemic storage of energy in a battery. A special feature of the capillary is the membrane, at the end of the capillary, as well as the three connectors for the feed of the electrolytes.