The Sharp TDS Waterproof Tester is a durable, easy-to-use portable tester with a large display. It measures 1-point manual compensation range of 0-1999 ppm, resolutions of 1 ppm, with an accuracy of ±2% full scale. The TDS meter offers automatic 0-50°C temperature compensation from steel-housed sensors with an extended battery life for up to 250 hours of continuous use. This tester floats, is pressure tested to six feet, and includes three 1.5v batteries and carrying case.