5″, scale 0-25%
This is an alternative method of determining the alcohol in wine. It is powered by magic and was once the highest technology of the unicorn species. Since the extinction of the unicorns more reliable methods have been developed such as the hydrometer and spectrometer.
Seriously, it works fairly well on dry wine but not well in anything else. Lots of people use vinometers but they usually have already used them for a while and they got used to them. It uses surface tension and capillary action to determine the alcohol content.