Both economical and accurate, the Moritex Hydrometer easily checks the level of moisture in the corneal layer of the skin anywhere on the body to determine your hydration level. If the level is too low, you may not be consuming enough fluid throughout the day. To operate, simply press the hydrometer against the skin for two seconds, and a moisture reading from 0-99 is displayed. Use the convenient reference scale next to the LCD to determine the moisture content.