4 in 1 Digital Water Tester TDS EC & Temperature Meter 0-9990 PPM Water Quality Tester Pen Accurate Backlit LCD Display for Drinking Water RO/DI System Aquariums Pool. Features precision water analysis, consistent TDS reporting, all-in-one water testing, purity testing made versatile, and health-conscious water testing. Specifications include accuracy of ±2%, TDS measurement range of 0~9990PPM, conductivity measurement range, and temperature range of 0.1~88.0°/32.0~176.0°F.