HDE Digital TDS (Total Dissolved Solids) Water Purity Quality Tester Meter ppm Pen Water quality impacts many aspects of your overall health keep a healthy family by measuring TDS (0-9990) parts per million TDS includes but not limited to mobile charged ions, including minerals, salts or metals dissolved be sure your drinking healthy! High quality LED flashing indicator and LCD screen make this high quality water tester an easy to use must have too Measures 0-9990 parts per million; pocket sized, light weight and portable Widely used for households, laboratory, pool, aquariums and spas