This is a Digital TDS Meter Tester, for testing the Filter Water Quality Purity, checking the performance of your water filter, check for hardness (1grain=17ppm), make sure you always drink pure water This item can be used in : water purifiers and filters, food (vegetable, fruits) & drink quality monitoring, pools and spas, aquariums, hydroponics.Hold function : Saves measurements for convenient reading and recording.Auto-off function : Turns off meter after 10 minutes of non-use to conserve batteries.Dual Range : Measures form 0-999ppm, with a resolution of 1ppm. From 1,000 to 9,990ppm, the resolution is 10ppm, indicated by drinking x 10image, Factory calibrated.Color: whiteMaterial: PlasticAccuracy: +/-2%Weight: 68gRang: 0-9990ppmItem size: 15.6*3*2cmBattery: 2 x 1.5V Button Cell battery (included)Note :Do not drop the entire TDS meter in water of dip beyond the maximum immersion level.This unit is not water-tight and is not covered under the warranty if water enters the unit.Package Includes :1 x TDS Meter Tester2 x 1.5V Button Cell batterys1 x User ManualNote: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.