Usage: Help you drink the safe and pure water, protect your health. Check the performance of your water filter and the hardness of the water you drink (1 grain =17 ppm). 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, +/- 2% High Accuracy Features: The meter can lock the readings to help you read and record. Turns off meter after 10 minutes of non-use to save batteries Easy to Carry:The testers is lightweight ,rasy to storage and portable.It fit in your pocket and you can take it anywhere. Please note: This meter CANNOT calibrate, It can be used in : water purifiers and filters, food (vegetable, fruits) drink quality monitoring, pools and spas, aquariums, hydroponics. 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 HOE TO USE: STEP 1: Remove the protective cap. STEP 2: Turn on the TDS Meter on. STEP 3: Immersing the meter into the water or solution up to the maximum immersion level. The height of solution should not exceed 4cm(from the pen point). STEP 4: Pour the pen gently in the water. Waiting for the reading to be stable. The measurement values of TDS meter was influenced by temperature much. So it needs time to correct the readings. STEP 5: The value of TDS will be fixed on the display between 10-30 seconds. Hold down the hold key to lock the value. STEP 6: Wiping the remaining water of the pen with cloth after you finish and re-cover the pen cap. Specifications : Color : Beige Accuracy : +/-2% Rang :0-9990ppm Item size :155mm x 28mm x 15mm Attention: 1.Please dont drop the entire TDS meter in the water or dip beyond the maximum immersion level. 2.Please dont store the TDS under the high temperament direct sunlight. 3.Please avoid to strike, press weighty and fall off. Package Includes : 1 x TDS Meter Tester 1 x Leather Case 1 x User Manual