This is a digital tds meter tester. For testing the filter water quality purity, check the performance of your water filter, check for hardness (1grain=17ppm), make sure you always drink pure water. Features: 100 percent brand new and high quality. 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 10 image, factory calibrated. Range: 0-9990ppm. Accuracy: +/-2 percent. Battery: 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. Item size:155 millimeter x 28 millimeter x 15 millimeter. Weight: 68 gram. Package included: 1 tds meter tester. 2 1.5v button cell battery. 1 user manual. 1 original leather case.