Proof and Tralles scales for measuring the alcohol content of a distilled spirit. Includes a plastic case that can be used as the test jar. Fill test jar with sample liquid and then float proof hydrometer in liquid. Alcohol content and proof can be read off the scale where the liquid level cuts across the hydrometer. DOES NOT WORK ON WINE OR BEER. Reads proof from 0-200 and alcohol from 0-100%.