Xcellent Global Digital Handheld TDS Meter With Backlit LCD for Water Quality Testing, 0-9990 ppm, 1 ppm Resolution, +/- 2% High Accuracy, Battery Included, Blue HG077 Ideal for water TDS testing like aquariums, swimming pools, water filters, and more Measurement range of 0-9990 ppm, 1 ppm resolution and 2% highly accurate and quick readings Data Hold Function: Freeze the measurement to view it out of the water; Temp function: Test the wate Auto-off Function; shuts off automatically after 10 minutes of non-use, low power-consumption for ye Lightweight, handheld design; factory calibrated;long lifetime battery included.