A PROOF AND TRALLES HYDROMETER DIRECTLY MEASURES THE ALCOHOL CONTENT OF DISTILLED ALCOHOL OR SPIRITS WITH A SPECIFIC GRAVITY LESS THAN 1.000. IT IS UNLIKE STANDARD BEER AND WINE HYDROMETERS BECAUSE IT IS CALIBRATED TO GIVE A DIRECT READING OF ACTUAL ALCOHOL CONTENT AND NOT THE DENSITY OF THE LIQUID. THIS HYDROMETER PROVIDES 2 SCALES OF MEASUREMENT WHICH ARE PROOF (THE US INTERNATIONAL REVENUE SCALE FOR PROOF OF SPIRITS) AND TRALLES (THE ACTUAL PERCENTAGE OF ALCOHOL). IT IS CALIBRATED TO GIVE ACCURATE READINGS AT 60F (15.6C) AND INCLUDES A CHART THAT PROVIDES THE ADJUSTMENTS NEEDED WHEN USING IT AT DIFFERENT TEMPERATURES.